That noise you just heard was the pssssssssffffft of a can of worms being opened. The subject: which Washingtonians are the best--and worst--tippers of cab drivers.

Terry Tahir is the guy who started this. He is better known as the hands on the wheel of Diamond Cab No. 245, and he is one of the more outspoken practitioners of a very outspoken profession.

Says Terry: The best cabbie-tippers in town are maids and other relatively low-income female workers heading to the far reaches of Northeast and Southeast. The worst are lawyers heading to upper Northwest.

"The reason maids tip you so well is that they really appreciate the fact that you're willing to go all the way out to wherever they're going," says Terry. "They know that if a cab won't take them, it's three buses, including two transfers, before they get home. And there's kind of a feeling of fellowship, too, between ordinary working people trying to make a buck."

You mean fellowship never fleets across the heart of a lawyer, Terry?

"Are you kidding? They're the guys who get in the cab and tell you which route to take, and then insist that you go that way even when it's the slowest way. They say, 'Who are you to correct me? I know my rights!' And then they tip you 15 cents for a run that takes 20 minutes."

What about conventioneers? Always heard they were good tippers. Also heard that the size of the tip was directly proportional to how much they'd had to drink.

"Some are good, some aren't so good," Terry says. If he's from Ashtabula, and this is his one trip a year, a conventioneer will probably be feeling like a sport. But if he has traveled a lot, and he knows how much things can cost nowadays, he'll probably be more modest, according to Terry.

As for alcohol loosening wallets, "It's not true," says Terry. "Never had a guy hand me a 20 thinking it was a one." Far more frequent are the times cabbies have to help a passenger to the front door -- where the guy is too zonked to remember to offer a tip of any size.

Capitol Hillies? "Pretty good tippers. Senators are better than Congressmen."

Lobbyists? "Usually good. Used to be better. Lot of budget cutbacks."

Kids? "They can be surprisingly good. You know, Mom tells them before they leave home to remember to tip the cab driver."

The bottom line? "I just wish people would realize that cab drivers make most of their living from tips. The difference between a quarter and 50 cents may not mean that much to you. But you multiply it out across a whole year, and to us, it makes all the difference in the world."