I refuse to use FacebookConnect (or whatever it's called), since it's my real identity being used. I imagine a lot of people are the same.
...Twitter...
I also don't have a twitter account, since I don't really see the point of it.
...Google...
Can you elaborate here? I'm not quite sure what you're referring to, though I feel like I should.
...OpenID
This is definitely a consideration, and has been brought up elsewhere in this thread. I'm definitely going to check it out, and see what's actually involved in it, since it seems a bit involved for something I'm not even sure will work.
However, I do hate it when sites don't let you signup directly and force you to use OpenID.
Same here. When StackOverflow launched, I didn't understand what they asking me to do to log in. I understand it now, but I've never had a reason to use my OpenID outside of the StackExchange network, so to me it's pretty much the same as having a single account for that purpose.