This topic has probably been done to death but then again I never get tired of such things.
I'd go with Kivan as well, the coolest bad-ass in BG1 after Minsc. Ajantis was just plain irritating and he hardly said a thing in BG1. Dynaheir wasn't much of a talkerin BG1 and I never really felt attached to her, as a result she got overshadowed by Minsc. Xan was cool but I doubt I'd have use for an Enchanter in BG2, maybe if he was a sorceror. As for Khalid, I hope he stays dead. Garret was just plain annoying in BG1 aklthough he was an ok shot with a crossbow and his Cyrano skit in BG2 was hilarious. Yeslick and Kagain were ok, don't really like or dislike them. I wouldn't mind having Shar-Teel in BG2, she would have potential to be a great NPC (and a possible romance). Faldorn was an eco-terrorist, she sucks. Xar and Montaron..... Oh yeah!