Is this BSOD a power supply problem?

I just built a new system with the following specs:

Intel E8400 @ 3.0ghz
Asus P5N-D nVidia 750i SLi motherboard
Zotac 8800gt 512mb
4gb (4x1gb) Patriot Extreme Performance 800mhz ram
320gb hard drive
Raidmax Smilodon Case (3 case fans)
Raidmax 500w PSU (included with case)
Windows Vista 64 bit

I keep getting a BSOD citing nvlddmkm.sys as the problem when I play games such as WoW or AoC. I've run MemTest several times for at least an hour each with no errors. I've tried playing with 2gb of ram or with 4gb. I've tried down clocking my ram and video card. I've tried 4 different nVidia driver versions (175.19, 177.79, 177.83, 177.89). I've updated my BIOS and chipset drivers. I've reinstalled vista twice. You name it, I've done it.

I now suspect that my PSU could be the problem since it clearly isn't the best in the world and it also only has one 12v rail supplying 22A. I believe my 8800gt suggests either 22A or 24A on the 12v rail. Could this be the cause of my problems?

If so, what would be a good PSU if I'd like to run either an 8800gt SLi config or a high end card within the next few months? I was thinking about this one:
http://www.newegg.com/Product/Prod [...] 6817371016

Would that be good? Any help would be amazing.