Alias, because, well... it's Alias.
X-Files! :lol:
Friends, because it's so light-hearted
Buffy, it brings back good memories
the OC, because, well, it fits. And I like that song.
Angel, I dunno, I just think it sounds cool, with the violin.
the old, original Felicity theme... the one that was kind of hummed by some female.