help with selections (psu, cpu, mobo, gpu)

hey guys, finally building a new machine now that the price drops have happened. I'd like to keep this as cheap as possible for the performance I'm aiming at here. I do pretty intensive Photoshop work, so I need a bunch of raw power. Here's what I've got so far:

Antec P180b
2gb OCZ 6400 ram
1 150gb Raptor (for OS & apps)
2 500gb Samsung Spinpoints (raid 1 for important data storage)
1 320gb Seagate for misc. storage

So I need a CPU, mobo, GPU & PSU (...right? forgetting anything?)

I was thinking q6600 over the e6600. Newegg has the q for $299 and the e for $229. I had read that they were both going to be $269...apparently not? or will there be some subsequent price adjustment? For the $70 I'd rather have 4 cores anyways though, right?

Mobo, I'm completely lost. I'll have 4 sata hard drives and a big graphics card. I'd like wi-fi, but thats not a dealbreaker. Suggestions? I don't feel like I really need P35, unless you can convince me the price difference is worth it. I'd like to keep this ~$100 if possible.

GPU, I'd like an 8800gts...which brand?

PSU, also completely lost. Obviously I need something that will handle what's here, and maybe some very mild overclocking in the future.

Thanks for reading all this, I'd really appreciate any help you can give.