Look for a branded PSU around 400W+
Have a look at Tomshardware GFX charts to compare the GFX cards. Either will do you fine for any recent games. They don't support DX10 though so you'll miss out on some eye candy on new games.
They don't run direct X 10 that may be a problem as I don't really want to upgrade the graphics card again in the next few months when I upgrade to Quad, what's sort of price are the DX10 cards second hands ?
Plus I want my set-up to play Crysis when it comes out ?