The power supply is just crap, don't get it. You need a decent one that can actually power properly a system like that (i.e. Corsair 520HX or Antec NeoHE 500).
All that ram sounds ok, however I tend to prefer Crucial Ballistix, but you won't go wrong either way. And there's no doubt you should get the GA-P35-DS3R over the other boards, it's pretty much the BEST P35 board out there, especially since DDR3 support is worthless at this point.
In my opinion the ONLY Vista version that isn't a complete waste of money (but still overpriced) is the Home Premium 64, the others are just simply not worth getting. I'd get the retail if you can spare the extra $100 and you like formatting your system as much as I do, just so you don't have to deal with M$ customer support every time you want to do a clean installation.
^^^ couldn't agree more. I've been recommending ballistix cuz it's micron d9 chip for dirt cheap. My ocz costs about the same, but doesn't o/c as well. But I got the ram for half the retail used. Can't complain. lol.
Other good o/c ram is G.Skill HZ (BLACK) & Buffalo Firestix (red).
If you go 64-bit, get 4 gigs of ram. 32-bit sees up to 3.5gb.
For mobos, I would touch only DS3R, ASUS P5K & ABIT IP-35-E or deluxe or pro. The rest can go to the landfill. Except for x38 boards.
Another vote for GA-P35-DS3R and Corsair 520HX. I think you'll be fine with 2 GB of RAM, at least for a while. Drop the DVD-ROM, the burner can also read.
I would save some money by going with 2 GB of RAM (rather than 4), OEM Vista (rather than retail), onboard audio (no sound card for now), cheap mouse and keyboard. Then I'd blow the savings and get an 8800 GTX instead of GTS You can always improve the mouse or add RAM later. If you like the idea get the Corsair 620HX, not 520HX.
Samsung, Viewsonic and LG make pretty good monitors as far as I can tell from personal experience. Make sure you get your monitor from a local store and you can check for dead pixels first, or make sure you can return the monitor without penalty if you find dead pixels at home.
You get better efficiency from the PSU if you don't get too close to its maximum output. From the charts I've seen, after about 70% the efficiency starts dropping ==> more heat in the case and higher electricity bills.
But sure, if the budget is limited by all means the 520HX will do.
honestly... unless you're running a dangerously big raid array I see no reason for the 620 to even exist, since the 520 already outputs 40A which can power any card and beyond, and the 620 is already dangerously close to SLI territory with a 50A output but just not quite there yet, which makes it easy money for the Antec TruePower Quattros and PC Power & Cooling Silencer 750.
And on top of that you're wasting more power due to efficiency not reaching it's peak until around 60-70% load, but then again I suppose some people that don't know how much power their systems REALLY need and how it work would feel much better with a more powerful unit.
Anyway both units are still top notch quality and you can't go wrong either way, just a PSU madman's ramblings... nothing else.