Well a few obvious things that stick out would be...
Too expensive a power supply..
Even if you were running 2 4870
X2's and a half dozen harddrives you wouldnt have to spend that much on a PSU..
This will more than suffice
WITH headroom for the build you listed...
Newegg.com - Antec True Power Trio TP3-430 430W ATX12V Active PFC Power Supply with Three 12V Rails - Power Supplies
You dont have to buy 800 rated ram, buy the 1066 since its cheap, and then if you upgrade youll already be set...
memory is cheap now so don't skimp
That Asus is nothing special, so save a little money and double the memory cap with this Biostar....
Newegg.com - BIOSTAR TForce TF720 A2+ AM2+/AM2 NVIDIA nForce 720a ATX AMD Motherboard - AMD Motherboards
if it were me I wouldnt waste money on Vista period right now, but ESPECIALLY not Ultimate...
If you have to buy Vista, get
home premium OEM...
Windows"7" or whatever will be out in a month or 2 likely and youll be stuck with an overpriced POS that youll be wanting to rid yourself of
I would personally invest in a better case than that, with the money saved from the PSU...
An Antec 300 is cheap and has amazing cooling...
If not a new case then a tinsnips and some bigger fans...
take that stupid swirl off the side of the case with the tinsnips or a dremel, and replace the window with stiff mesh and mount a 120 - 140mm fan there