Voted for:
Konata - Pair her with Kagami and these two alone make sure the series are as funny as hell + she's an otaku.
Kagami - Pretty much the same reason. Konata's still my No.1 though. But I think you all figured that out already, judging by my avatar.
Misao - Long story made short; The fang, the seiyuu, the character design, the personality. Is there anything not to love?