ok what to choose

Buying a pc depends on the games you play, IMO, just like buying a game console for the GAMES. Go through the benchmarks of the games you play from the top drop-down menu.

http://www.tomshardware.com/charts [...] 1,758.html

Then you can decide on a mobo. GA-EX38-DS4 or EVGA 780i.

I would leave the 780i on the counter and get the X48. And that's exactly what I did a few months ago, so I yes, I put my money where my mouth is.

As to the video cards, I would get a 4870, which I also did. The only other good option in the price/performance area is a 9800 GTX or 9800 GTX+, if you do folding at home. The 8800 Ultra cards are too old in architecture. Good cards, but old and overpriced for what they are. Unless you have a very large monitor, you don't need X2 or GX2, XFire or SLI, so save your money for something more useful, like a better CPU such as a Q9550 or Q9650. Such are my opinions.

OK, in that case, I'd go for a 4870 X2, or perhaps two 4870s in Crossfire.