I avoid FB connect - sites/services I try don't need to be linked to my identity on Facebook, that's just too private, sorry.
But I think you should have Facebookless login if you care about early adopters: too many of them are indeed "outliers" you've identified above. I also think you should have facebookless option simply because it's good for the Internet: I wouldn't want to see so much of it being controlled by a handful of large corps.
[1] http://www.quora.com/How-much-is-Facebook-Connect-limiting-Q...