chrisjur summed it all up pretty well.
If you're looking for loungy, Number 9 is probably your best bet.
JR's and Cobalt are definitely still there, JR's best night is Sunday night for $2 Skyy or Coor Lights.
Town is 18 and over on Friday nights so should be avoided unless you want to relive you're high school prom (though slightly gayer). Saturdays though can be a great time (and are 21+).
Nellies is a decent bet, especially if the weather is nice as they have a large rooftop deck.
Secrets really is out in the sticks. However, they partner with a black car service that, with their discount, is about the same price of a cab. You can generally get the number from their ad that is always on the inside back cover of Metroweekly (local gay rag which, incidentally, can give you a pretty good rundown of what's going on)
If you're on a budget, JR's does an open bar on rail and drafts from 10:45-11:15 on Fridays. Cobalt does free vodka drinks from 11pm-12am, also on Friday's. Number 9 does 2 for 1 on ALL drinks from 5-9 every day of the week. And of course there's JR's $2 Skyy and Coors lights on Sundays.
Number 9, JR's and Cobalt are all relatively close to each other, while Nellies and Town are right next to each but not close to the other three.
Lastly, all-you-can-drink Sunday brunch is pretty much an institution here in DC, and can be found all over the place. Level One, Scion and Masa 14 are all pretty good, but reservations recommended.