Yes, he does already have an OS and HDD from his previous computer. As for why there's a nVidia card, he had an 8800GTS already and wanted to SLI it. But I can see the reasons about the mobo. It was recommended to me, but it doesn't seem to fit the bill.
Intels are nice, but I usually prefer AMD. They are usually cheaper mainstream, and the small upgrade in performance you get from Intel isn't worth the money usually in my customers eyes.
The BE edition of the Phenom, with the 9950 being the newest tend to overclock well actually. The multipliers are unlocked (which I'm sure you knew already) and I've gotten 2.6Ghz Phenoms to 3.1 or 3.2Ghz stable, with no problems. I usually prefer water cooling over air, but thats just a personal preference.
I had already planned on flashing the BIOS to the new version update, but as is I'm looking for a more suitable mobo. Looks like the recommendation came up flat. Trying to find that that handles both 140w on the CPU for Phenom and has SLI.