I'd change my HN name to Rory if I had the choice: I'd rather have this tied to my name.

I'd much rather have real names used on blogs and news sites, personally. It feels cozier that way. When I comment on other blogs I always use my full name.

Also - apologies, I was in a rush to class earlier - there's a difference between a social network and a social news site, as you said. Facebook's killer idea works because Facebook is a social network. There're other situations where using Facebook for comments would be really nice. Commenting on essays and academic papers, for instance, because when you're writing about intellectual work it's useful to talk with the weight of your name rather than anonymity.