9. WHEN do you plan to build it?
End of April
Ok. It's relatively pointless to suggest a build or a specific component one month in advance. Come back in 3-4 weeks, we'll sort that out then.
I have some general comments though to get you thinking:
Motherboard First off, you can't put a 3930K on an LGA1155 motherboard. It needs the LGA2011 socket. Those motherboards are considerably more expensive than LGA1155 motherboards. If you were going to stick to LGA1155, the Z68 chipset would be a better choice than P67. But one month from now, we'll probably have the 7-series chipsets around, meant for Ivy Bridge processors.
CPU The tasks you listed would probably benefit from the hexacore and your budget allows for it. However, keeping in mind you're also looking for bang for buck, it would make more sense to go with a hyperthreaded quadcore like 2600K or its upcoming Ivy Bridge equivalent, 3770K. This is especially true because of Ivy Bridge, as it will slightly bridge the gap between 2600K and 3930K in terms of performance.
How often do you plan to upgrade? Don't buy the hexacore to "future proof" your PC - it's better to buy a part like 2600K that costs half that, and save the other half to a CPU upgrade a couple years from now because tech evolves fast.
RAM RAM speed is largely irrelevant on Sandy Bridge, above the 1600Mhz mark. Up to that point, price/performance is good, but anything faster costs more than
it's worth. Buy 1600Mhz CL9 RAM, usually can be had for $40-45 per 8GB.
GPU The new GTX 680 is definitely better than HD7970. Check out the
review.
SSD Good, Samsung 830 is another choice, in fact better if it costs the same.
Case&PSU Unless you're planning for SLI/Crossfire, the case and power supply are definitely overkill. A mid tower will have enough space and cooling capacity for any single GPU setup. And a 3930K + GTX680 based system, overclocked, will not need more than a good quality 650W-750W power supply.
Cooler Hyper 212+ would only take you so far with a 120W hexacore. 2600K will get to 4.5GHz or so at acceptable temps with a 212+, but to reach the same with the hexacore you'll probably need something with more mass and fin area, shouldn't be a problem with your budget. But since I'd recommend the 3770K, you
should be fine with 212+, however there's some talk of 3770K running hot because of the more concentrated die so you may need better cooling than for Sandy Bridge. AS5 is not needed as heatsinks typically come with thermal paste; besides, there are better choices than AS5 (Noctua NT-H1 for example).
Network Why do you need an ethernet adapter? Motherboards already come with network controllers. You'll only need an adapter for wireless.