That ASUS board is very, VERY good. Much better than any current DFI board, and the DFI expert board has tons of problems like killing CPUs and stuff. If all the DFI fanboys here try to tell you the expert is better, just head on over to XtremeSystems.org to get feedback from people who actually own them
Also, instead of getting two 7800GT's, get one 7800GTX 512. The dual 7800gt's will not help at all in games that arn't made for SLI, and they will only provide about a 40% speed boost in games that are optimized. The 7800GTX512 will cut through all the latest games up to and including FEAR like a hot knife through butter.