I already have an XFX 8800GT that I bought a while back and would like to refrain from buying another graphics card unless absolutely necessary. I already have a Fatal1ty champion sound card as well.
Looking to put the following together... any suggestions are welcome. I have a 2k budget and would rather stay under that than spending every dime. This will mostly be for Diablo III, and various online games (minimal FPS). Watching movies in HD and editing home videos.
Western Digital Caviar SE16 WD5000AAKS 500GB 7200 RPM SATA 3.0Gb/s Hard Drive - OEM
PC Power & Cooling S75QB 750W ATX12V / EPS12V SLI NVIDIA SLI Certified (Dual 8800 GTX and below) CrossFire Ready 80 PLUS Certified Active PFC Power Supply - Retail
Your system sounds similar to one that I built a year ago. I had a similar budget and goals, although my components are of course older by now.
I think your PSU is overkill. You really don't need anything more than 500w. I'd recommend the Corsair 520 or 550W ... I have the 520 in my own computer. I don't know if noise is important to you, but the Corsair PSU would also be quieter.
The 750i is a more gaming-oriented motherboard than I think is necessary ... I think the P45 would be a better choice. In general, the P45 is considered to be more stable and reliable. The only caveat would be if you eventually wanted to do SLi, but it sounds like you are not planning on getting a new video card any time soon. By the time you get ready to upgrade, getting a newer single card will be a much better option. In general I think that dual GPUs seem to be mainly used by people looking for bragging rights and are not really beneficial in real-world situations.
There are better CPU coolers out there for lower prices. The Thermalright Ultra 120 Extreme is generally considered to be the best air cooler, while the XIGMATEK HDT-S1283 performs almost as well for much less money. Either of those two would perform better than the Zalman.
You might want to consider upgrading your hard drive to the newer 640GB Western Digital ... it has more recent technology and doesn't cost that much more. I don't know how serious you are about video editing, but you might want to consider getting two hard drives so that you could have a scratch disk for better performance.
Also, you should ask yourself if you really need Vista Ultimate for your goals.
Everything else seems fine. In general, you made some good choices. My computer also has a quad core (the older Q6600) and 4GB of RAM and a 24" LCD and it works fantastically.