1) Will that PSU be enough to cover that system?
2) I know the VelociRaptor takes a lot of heat on these boards, but I'm looking for a good solution to the HDD problem: I want a fast, small drive for my OS/games and a hefty secondary drive for my media. Any other suggestions?
3) How am I doing on cooling, given my overclocking goal? Would you recommend any more aftermarket cooling?
4) That build is about $200 short of what I'd like to spend. Where would you recommend putting the extra money?
I bought and built a computer just a couple weeks ago that is very similar to the one you are looking at buying. The specs are listed in the following link (I upgraded to the Antec 1200 and doubled the ram).
1) EDIT: On second thought, you are going to want to upgrade your PSU to ~850W to power that rig.
2) I have 2 500gb 7200rpm HDD's in RAID 0 and they are really fast. To be honest, they are most likely faster than the velociraptor, cheaper, and have larger capacity. Even with those RAID HDD's, it isn't much a gain over a 1tb hard drive. I would recommend against the velociraptor and spending the extra money elsewhere. However, that is more of a personal choice. To each their own.
3) You shouldn't have any problem hitting 3.2 GHz, especially with aftermarket cooling and the 1200 case. If you are trying to max out your CPU overclock, I would recommend a beefier cooler, but it is unnecessary for your OC goals. Also, consider a small 40mm fan for the Northbridge of the MB. The Northbridge does get rather hot and a fan only costs a couple bucks, but it is optional.
4) Upgrade the 275's to 285's. They have more power, use less energy, and run cooler.
The 1200 is a big case. I have tons of empty room in mine. It definitely helps with the cooling, but I just thought that I would warn you. It is great having the flexibility for future upgrades. The 275's and 285's will not fit in the 902 case. If you are considering a smaller case, then you would have to pick a completely different line of cases.
With that MB, SLIing with two dual-slot cards till eliminate 3 PCIE slots and 1 PCI slot from use.
Use this ram instead. It is $50 cheaper ($65 with MIR).