You shitting me....400-550 Watt? ....Get 750-1000 Watt, you'll need the extra juice.
Up the RAM to 6-8GB to compensate for the overkill 6 core 3.2 GHz processor and it looks fine in my eyes.
(Bearing in mind I spend most of my time buying parts, assembling rigs, and selling them to people I know.)
DinoPC is great btw, I bought the barebones/skeleton/base of my current PC from them. Although, it's comming up for two years in July 2011, so i'll need to think about replacing and upgrading parts too.