Could he please link the Rosewill PSU? Not all the Rosewills were very good. Newer ones were solid but not the older ones.
Also I disagree with Unknown on CPU, MB, GPU and HDD choice.
Check out my $850 build here:http://www.squidoo.com/electronicandmore
Since you don't need the HDD or possibly the PSU, that's $145 off which gets you to about your budget.