Yep, I'll throw in a down-vote for live chat. The forum already has private messaging for the truly private conversations and otherwise it's nice to have the dialog between members recorded for future reference and in an easily searchable format.
And another note: even if the chat data was recorded and was easily searched, chat dialog is usually AWFUL. Sentence fragments, posts based on immediate emotion, no proof reading, LOLZ and excessive use of emoticons.. What I'm saying is that it's usually painful to read through
I want to add that I'm no Luddite. I just hate to see poorly integrated addons being tossed at websites. They rarely benefit the system as a whole (as in the majority of users; current and future). In this case I'd say clean, accessible data trumps fast 1-on-1 conversation.