What should one expect from a restaurant with a name like Carlos O'Kelly's? Baskets of boiled potatoes with a side of salsa perhaps? Tacos stuffed with clover and beef stew? Guinness stout with an order of enchiladas?

Washington can claim a number of restaurants specializing in mixed cuisines, but Fairfax appears to have cornered the market on Mexican-Irish establishments with the opening of Carlos O'Kelly's.

As it turns out, however, this is more Mexican cafe than Irish pub, an enormous adobe box carved into three dining rooms and a southwestern-style fern bar (cactus bar?) off the foyer. To be sure, on a busy weekend you might well become acquainted with the lounge, which serves as a holding pen for diners who have been asked to wait up to 1 1/2 hours for a table. And it's from the drink list that you're likely to encounter the menu's limited dual-nationality offerings -- beers from Mexico and Ireland and margaritas served Carlos-style (up or on the rocks) or a la O'Kelly (frozen, in a range of fruit flavors from peach to strawberry and cherry).

As for the menu, the only hint of anything Irish is an unenthusiastic appetizer of fried potato skins and melted cheese -- but with a sprinkle of green chilis.

Instead, the bill of fare emphasizes the usual array of what we've come to expect from family-style Mexican eateries: tacos, guacamole, seafood salads, chimichangas, fajitas, tortillas stuffed with meat, seafood or chicken, and the ubiquitous combination platters.

There are several nice touches, however. One of the most interesting appetizers sampled was the Mexican pizza, an enormous albeit thin and lacy tortilla crust topped with fresh taco accouterments: grated cheese, ground beef, lettuce, tomatoes and the like. It's light and tasty stuff, but perhaps too much for a single diner -- plan to share it as a starter or select it as an entree.

The thin strips of deep-fried chicken strips ("Chicken Fingers") were no more exciting than the fast-food variety, and an accompanying honey-mustard sauce was heavy on the sweetener. I'd opt to munch on the complimentary chips and salsa that precede a meal here; the corn nachos and piquant dip are a pleasant match, the perfect foil for the bar's huge margaritas.

I found little to distinguish most of the entrees from the fare served in a hundred other taco houses, save for some pretty dismal refried beans and some above-average fillings. Fajitas -- char-broiled strips of beef or chicken served with grilled vegetables and wrapped in flour tortillas -- provide perhaps the most adventurous eating. In addition to the main components, there's a generous side dish ("Here's your fixin's plate," said our waitress) of guacamole, sour cream and scallions, a chunky, zesty salsa and grated cheeses with which to stuff the tortillas. Stray not from the pork-chicken-beef fillings, most of which have been reliable. The seafood-stuffed offerings we sampled smacked more of refrigeration than of freshness, and even the menu was vague, referring to an enchilada's filling of "seafood mix."

Carlos O'Kelly's sticks rather close to its south-of-the-border identity: The waitresses are costumed in colorful peasant dresses, the waiters in more formal black attire, and the music is a continuous stream of Mexican ballads (which can get a little tiring by dessert, frankly.) But service is tops, friendly and efficient. And at least one senorita won points with my table when she returned with a companion's fajita remains, neatly secured beneath swan-shaped foil.

Dessert features yet another tortilla (this one filled with cinnamon-spiked, commercial-tasting apple filling and topped with ice cream) and fried ice cream, a small glob of which was coated with what appeared to be Rice Krispies laced with honey.

Despite some of its shortcomings, Carlos O'Kelly's is as warm and inviting a spot as most of us are likely to visit this winter. Food can take a back seat to comfort on occasion, but at such modest prices, I'd hesitate to complain about the exchange rate.