I would recommend the AMD setup you have picked out with a few caveats:
Firstly, if you haven't noticed, intel's Core 2 Duo comes out late July (maybe August for us consumers) and will be the better build for your money. Also, any reason you're not going AM2?
If you can't wait, then read on:
Avoid the rosewill PSU like the plague.
The silverstone might be fine - it's expensive enough, but I haven't really heard much about it and reflexively recommend either Fortron or Seasonic for your build.
You seem to be building a gaming rig, in which case you will want 2x1GB of memory. You can get the 2x1GB 2-3-2-5 patriot kit for $120 after rebate, and the corsair for a little more. On your AMD build you have 4x512 picked out, and that's a bad idea. You get better performance for less money with the 2x1GB sticks I mentioned.
I'm not sure whether to recommend the 1800 or the 7900GT for a video card solution - from what people say the performance is dictated by whichever game you're playing. They're about equal from what I can tell. Maybe spend $40 less on the 7900GT and use it towards another component.
For a sound card most people recommend spending the extra 30-40 for the X-Fi Xtrememusic. I have never owned an audigy 2zs but I do have the x-fi and I love it.
For a motherboard that ASUS looks fine. I have owned asus in the past and have been pleased.
For the processor that 3800+ venice looks fine, but it's out of stock. The 3500+ is a perfectly good alternative for a few bucks cheaper, and will overclock to 2.4, 2.6 and beyond without much trouble. If you have no desire to OC you might consider looking elsewhere for a 3800+ venice.