Before you touch nvidia, you might want to read these stories and follow the links.
http://www.theinquirer.net/gb/inquirer/news/2008/08/12/nvidia-g92s-g94-reportedlyhttp://www.theinquirer.net/gb/inquirer/news/2008/08/02/nvidia-chipsets-deadhttp://blogs.zdnet.com/hardware/?p=2203http://blogs.zdnet.com/hardware/?p=2397http://blogs.zdnet.com/hardware/?p=2308There are other articles. It appears to extend beyond just notebooks into desktop cards and integrated graphics. Apparently, it's a thermal cycling problem where some connections get fatigued and break.
Also, if you go with the PHENOM you want to check to make sure that the MB can handle the 125W load. Apparently, a lot of MB had to be redesigned for the increase in wattage of the higher end PHENOMs. The original Phenoms were 95W. Also, the Phenom chips are rumored to be bad overclockers and really eat power as they overclock.
The Q6600 ( 65NM, 1066 FSB, 2.4 GHz, 8MB cache ) is probably a faster chip, draws less power, and many projects use the intel optimizing compilers. I'd consider paying a little more for the Q9300 (45 NM, 1333 FSB, 2.53 GHz, 6MB cache, some new FP instructions and some internal improvements).
From what I've read, it looks like AMD won't begin to catch up until the transition to 45nm at the beginning of next year (Server 45nm chips in 4Q 2008). Unfortunately, by then Intel will have the nehalem chips (Core i7) out with integrated memory controllers and some improved vector FP instructions. I hate to see AMD so far behind but they just don't have the resources that Intel does and Intel has done excellent work since the P4 fiasco.
Hope this helps.