Here's my list so far:

Hotel Kamp, Finland: gorgeous, classy, comfortable, incredible selection

W Mexico City: always happening, though I can't seem to do my traditional "bar lean" there because the stairs get in the way and the servers behind the bar are lower than you.

Sheraton Yankee Clipper: Yes, it's a dump, but there are only two bars like it in the world: It has a glass wall that looks into the deep end of their swimming pool! Featured on a movie with DeNiro (Link here)

Sheraton Delfina Santa Monica: nicely appointed, great lighting, little bit of a family scene

St. Regis Monarch Beach: excellent service, great locale

Westin Peachtree Atlanta: the restaurant revolves around the bar in the center, so you can peoplewatch without appearing nosy!