i live in takoma park and like it a lot. nice little downtown area (only one bar though) and maybe 25 minutes to downtown.

in the city, you're mostly gonna be doing urban riding (lights/stop signs every block) with a few exceptions. hains point is one, rock creek (really only good on the weekends) is another. the national arboretum sucks to get to but is a really nice little loop once you're in there. also the c&o canal is good if you just want to stomp on the pedals (you'll want at least 28mm tires for it though).

if i had to pick a place to live in the greater metro area based on the riding, i'd pick frederick md. no contest. i know this is the road forum but the mountain trails up there are awesome, and i'm sure you could string together some epic road rides as well.