Another AMD vs Intel CPU question

As long as money isn't the issue there is no good reason to get a amd chip over and intel chip. clock for clock intel beats the crap out of the amd chips. And when overclocking is thrown into the equation it's game over for AMD. Intel chipsets are generally considered higher quality then ati and nvidia chipsets nowadays as well.

Micro ATX boards are fine IMO. But Micro ATX cases often have limited cooling abilities and limit the size (performance) of the CPU cooler itself. So I would really build a system with a full atx board and case. ATX cases made from aluminum can be very light wieght

Ditto all of the above, stick with intel and go with ATX case. Micro ATX also is too small for most beefy sized video cards, EI dual slotted cards

I sadly would have to agree with Dekasav as well...but I guess the closest thing to it would be a Phenom 9950 or so...

Not really. The Phenom 9950 cannot OC to 4GHz on air. The E8400 can.

TBH I would probably go quad. But thats just me. VALVe released the demo for those who preordered for Left 4 Dead (yes I did and love it, everyone will get the demo on the 11th) and it includes a newer more advanced version of Source that can use quads to their potential. It was using my Q6600 @ 3GHz and about 50% across all 4 cores the whole time I was playing. It increased performance nicely too.

But then again not many companies are focusing on MT. So a E8400 would be a great choice too.

I personally would also go quad core instead...but thats just me...

The closest thing that AMD has to the E8400 is the X2 6400+, but the X2 6400+ is an older part that runs hotter and is a little slower than the E8400. AMD has pretty much concentrated on quad-core and triple-core CPUs. If you run things that are multi-threaded, a Phenom would be faster than the E8400 for about the same price, but none will beat the E8400 at single-threaded or two-threaded applications at the moment.

It doesn't matter as gaming depends on the GPU and the CPU. You can put the same CPU and single GPU in a mini-ATX as a standard ATX board, so it should be no different. Buy whatever one fits your case better or has the features you want.