Clematis street has gone steadily downhill thanks to Mayor Louis Frankel (but that is another discussion). One of the sole survivors has been the ultra-hip Lounge, owned by the people who have brought you Respectable Street, which is also cool in it's own way, but not hip. The Lounge has a wonderful ambiance of dimmed lighting and a beautifully designed interior, as well as a cute patio out back with some greenery and wooden seating. The Lounge has a sushi buffet for happy hour that is a nice touch, I mean where else will you find that?! They also consistently have DJ's or other live music and have some seating out front as well.
If you are brave enough to hit up Clematis these days, despite it's increasing shadiness, definitely patronize the Lounge (and perhaps O'Shea's while you're at it!)
Check out their myspace page here: http://www.myspace.com/theloungewpb