If you're getting an Asus board, which is awesome, go with Corsair XMS. OCZ and Asus don't play well together. And I second the notion for a 7900GT. The Radeon series is loud, hot, and while it has the ability to render HDR and AA at the same time I guarantee you won't care. If you get an eVGA like I did, you can trade in your "old" video card within 90 days and get a newer card, and you just have to pay the difference.
If you do anything with Linux, do yourself a favor and get an nVidia card - ATI's drivers are terrible for all platforms but especially for Linux. And drivers decide what performance you get.