Mixing ATI and NVidia

Won't matter, you won't be doing SLi on it but a single card is just dandy.

Yeah you'll be fine, I have a X1900XTX in my AN8 SLi board, and of course it works perfectly fine. It'd be kinda dumb for them to lock out potential customers by only allowing their own cards on it.

I agree it would be dumb, but at the same time... Who knows. PRobably just being paranoid. Thanks for the answers.

That's not true at all. Maybe you could get a Crossfire board to run SLi if you find a hacked solution for it, but there's no guarantee. If you want SLi, get an SLi board or, if you must, one that is not officially SLi but has been proven to be able to run SLi. Same for Crossfire.