What's with the 6GB ram..?? If you are planning to get 3 x 2GB ram set then drop the idea and get 2 x 4GB (total 8GB) ram set.. You get more memory and also the dual channel benefits.. As for the PSU, the Silverstone unit looks good here and should have no problems handling a couple of GTX 580's..
Sorry i ment 8GB. So silverstone is better? Thank you all (yet again)