Alone in your home, going out for breakfast may seem an original idea. But once you arrive at McDonald's you discover it was not so original. The coldest day of last winter, at 8 a.m., the lines at one McDonald's reached to the door, and even during one gas crisis or another, the fast-food breakfast lines were longer than the gas lines. One of those oft-quoted authoritites, a public opinion survey, found Americans eating breakfast away from home more than once a week (5.1 times a month, to be exact). And many of those breakfasts are at fast-food restaurants. It is easy to see the appeal: They are inexpensive, usually $1 to $2, though your nearest drugstore counter may offer a cheaper breakfast. They are quick; though sometimes the line may lag 10 or 15 minutes, you can often be in and out before five minutes have passed. The food is standardized, thus reliable, and people tend not to like surprises for breakfast. Finally, the premises and food tend to look pristine, particularly once the food has been packed in all that hospital-white foam plastic. Generally the food stays hot until it reaches your desk/kitchen.

But, alike as one fast-food breakfast is to another, and one fast-food chain is to another, there are subtle differences that make people staunch defenders of one or another. Fierce arguments continue as to whether Roy Rogers' or McDonald's fried potato cakes are superior, and there are Burger Chef supporters who would never consider a Burger King breakfast sandwich. Basically, however, fast-food breakfasts come from the same mold: scrambled eggs with sausage, pancakes, shredded potatoes formed into cakes and deep fried, and a breakfast sandwich of fried or scrambled egg, ham or Canadian bacon, and cheese. But here, in a survey of fast food breakfasts, armed with thermometer and scale, I have explored the subtler mysteries of the art. Burger Chef -- all locations, Monday through Friday, 7 to 10:30 a.m.; Saturday and Sunday, 8 to 11 a.m.

What distinguishes Burger Chef from its competitors is its lack of any outstanding characteristic. Except for the low price -- and dismal quality -- of its coffee, Burger Chef serves a pure middle-of-the-road breakfast. For $1.29 ($1.19 in the suburbs) -- a middling price -- you get what the menu calls "scramble eggs and bacon" packaged on a plastic plate with a high-domed cover. The eggs were only slightly rubbery, generally soft and scrambled into layers. With them were two thick slices of soggy toast, grape jelly and two slices of bacon. Salt was forgotten. That musty, watery coffee spilled. Burger Chef's Sunrise Sandwich was as soggy as the toast, but it came in two sizes (the larger one, at $1.19, being a distinctly better buy than the 99-cent size); both had the clever touch of a slice of tomato with those typical scrambled eggs, American cheese and Canadian bacon. It's a nice fresh wake-up taste in the middle, but the larger sandwich could use a second slice of tomato. The rest of the menu is limited to Danish (45 cents), juice (40 cents) and milk (30 cents). Ready in four minutes, breakfast came with a smile and a "sorry for the long wait." Burger King -- only 16th and K Streets NW, daily, 7 a.m. to 10 a.m.

Everything that can be preplanned is done well at Burger King. The English muffins are Thomas', and fork-cut so they crunch and ooze butter. The sausage is spicy. The ham in the ham-cheese-fried egg sandwich ($1.04) has some chew to it. The hash browns are good. The coffee, served with real cream, was the best brew of this survey. But the last-minute things can go wrong at Burger King. While service was as chirpy and sweet as it can be, it doesn't compensate for a 15-minute wait for the food. The coffee was packed up before the order was cooked, so it was only lukewarm when the order was ready. While plenty of salt, sugar and butter was packed in the bag, the butter was placed on top of the hot eggs, so it melted through the bag. But the main disappointment was the scrambled eggs. They had been barely mixed and hardly cooked, a gooey mess that was difficult to face on an empty stomach. The egg-sausage-English muffin breakfast cost $1.34 (75 cents without sausage) and could be good if somebody made sure the cook knew how to scramble an egg. Holly Farms -- all locations, daily, 6 a.m. to 11 a.m.

Holly Farms has the most eccentric fast-food breakfast: Some of the best and some of the worst. What really made me nervous about breakfasting at Holly Farms was that everyone else was ordering fried chicken. What did they know that I didn't know? Maybe they knew that the Holly Brown potatoes are a mush of semi-mashed, oversalted gray potatoes, that the Texas French toast is a weird deck of dry bread triangles with a layer of scrambled egg glued to the top layer. Waht I do know, though, is that the choice of mix-and-match breakfast makings is the broadest among the fast food franchises. You can choose one, two or three eggs, with or without sausage, bacon, potatoes, biscuits and coffee. Something matching the competitors' two egg-sausage-potato-bread combination costs $2.09, the highest of any. With only one egg it costs $1.59. Holly Farms does have its assets. Its sausage is good and spicy, its bargain-priced pancakes (99 cents for two, including sausage) are heavily buttered and well flavored. And its Holly Eggwich -- moist scrambled eggs with bacon and lots of gooey cheese on a well-buttered English muffin -- costs 99 cents. Holly Farms wavers on the brink of being too slow for fast food, and in its disorganization served me the coolest (150-degree) coffee of any except Burger King. But it is a good place for breakfast if you don't care for early morning regimentation. McDonald's -- all locations, daily, 6:30 or 7 a.m. to 10:30 a.m.

Mcdonald's isn't on the too of the heap for nothing. Its Egg McMuffin -- English muffin, fried egg, cheese and Canadian bacon -- and its golden-crisp cake of hash browns are high on the list of historic American inventions. The sandwich costs 99 cents, the hash browns 35 cents. The line for them tends to move slowly, and there is no visible photograph of what you get, as at other fast-food restaurants. Presumably everybody knows what an Egg McMuffin looks like. But not everybody is prepared for the scrambled eggs a la McDonald -- square cut from a huge pan of eggs, tough and unappealing, dumped on top of the sausage so it grows soggy and wet before you eat it. It all costs $1.45 with hash browns, $1.15 without (but the hash browns are the highlight). You can also buy pancakes, Danish and English muffins with jelly (but no butter). The kind of thing that keeps McDonald's successful is that its coffee is one of the two cheapest in this survey (25 cents, equalled only by Burger Chef) and the hottest of any tested. The kind of thing that keeps its competition alive is that the coffee -- weak, but still emitting a bitter after-taste -- was one of the two worst (the other being Burger Chef). Jack in the Box -- all locations, daily, 5 a.m. to 11 a.m.; Breakfast Jack served all day.

You hardly have to slow down in your daily routine to breakfast at Jack in the Box. Drive up, place your order in the window, hand the cashier a dollar and even get change before you drive off munching a Breakfast Jack -- a hand-torn half slice of boiled ham with fried egg and cheese on a hamburger bun, at 90 cents the cheapest breakfast sandwich in this survey. Jack in the Box also serves the only fast-food breakfast omelet, a flat, crisp-edged fried square of that certain moist, oily nature that has kept the all-night diner alive. It comes with ham and cheese, with double-cheese or with ranchero sauce, a kind of spicy thickened tomato juice with red and green peppers, which is not bad at all. And best of all -- besides the fact that it costs a modest $1.05 -- is its accompanying English muffin -- well toasted, crunchy, buttery. The coffee is so weak you can see the bottom of the cup when it is full, and its non-dairy creamer does not help. But it is hard to drink coffee while you are driving anyway; Breakfast Jacks you can eat with one hand. Red Barn -- only 607 N. Randolph St., Arlington; weekdays 7 a.m. to 10 a.m.; weekends 7 a.m. to 11 a.m.

Breakfasting at Red Barn requires a strong commitment. Its prices are high ($1.49 for eggs with sausage and muffin, $1.19 for pancakes with sausage, 45 cents for blueberry muffin or hash browns, 40 cents for an English muffin, 45 cents for milk). Breakfast is served in only one location. And the coffee is weak, served with non-dairy creamer. But, along with excellent, scrambled eggs, there was one reason for such a commitment: the waffles. At $1.19 ($1.79 with sausage) they were very light, very crisp and delicious, with rivers of butter melting in the grids. But the waffles have been removed from the menu since my visit. I knew they were too good to be true. The hash browns are fine; the sausage is savory, though chewy; and the soft, moist flakes of barely set scrambled eggs are as good as I hope you make them at home. Skip the sandwich, chintzy in its stuffings, and don't bother with the pancakes or blueberry muffins unless you happen to prefer them heavy. Smile back at those cheery servers in green caps and orange shirts, but check your order before you leave, for they were better at smiling than at remembering to pack everything. Roy Rogers -- a few locations; weekdays, 6:30 a.m. to 10:30 a.m.; Saturday and Sunday, 7:30 a.m. to 10:30 a.m.

Despite your having to pack up your carryout breakfast yourself after choosing it from the cafeteria line, Roy Rogers (borrowing from its competitor's musical claims) was the one that does a lot for you. Except for coffee, its prices were lower than its nearest competitors until a recent price increase equalized the competition. The scrambled egg breakfast is now $1.45, including a biscuit with the sausage and ranch fries. Its pancakes and sausage are $1.15, its ranch fries 30 to 35 cents. Doughnuts and biscuits are now 30 to 35 cents, Danish 40 cents. You can see your choices in photographs above the serving area, and except for rampant blandness, you get what you expect. The scrambled eggs are good -- soft and flaky -- and the ranch fries equal McDonald's hash browns. While the coffee was hot (and weak), the egg-cheese-sausage sandwich had grown cool in the cafeteria line, and the filling was swamped by too big a roll. A little spice in the sausage, more punch to the coffee and a reproportioning of the Early Rider sandwich would have improved things. But now, with the new prices, Roy Rogers has shifted from the breakfast bargain of the breakfast bars to just one of the crowd.