- 30 Rock--the music and the quick cuts between the characters, coupled with the NYC backdrops, immediately make the show's tone and setting clear, and put you in an appropriately manic mode.
- The Office and Parks and Recreation--Both establish that while we're in a small universe, we're in a small universe that's not without charm and quirk (or, apparently, Hutts), and where people have ambition beyond that world (even if that ambition fails). (And looking forward to see how they tweak the Parks and Rec credits to reflect this season's cast changes.)
- Parenthood--This (which oddly doesn't seem to be available on YouTube) may actually be my favorite opening sequence on TV right now, with its mixture of Bob Dylan's "Forever Young" and real childhood photos of the adult cast through the years evoking the show's tone just right.
There are a bunch of other solid ones on NBC (and its cable sister networks) now--Chuck, Friday Night Lights, Psych, Royal Pains--where the theme music and title sequence combine to effectively establish tone and character, along with a number of classic NBC ones (Hill Street Blues, ER, Friends, Cheers). It's an art we're losing, and one I wish we weren't.