first off,..4gb of memory is overkill....512mb of memory is enough...1gb is heaven....and 2gb is the heaven in heaven and 4gb is overkill. and i also wouldn't recommend using all dimm slots.
ok for your 2 HD,..what are you planning do with the second,..is it for storage? mirror the first HD? of RAID 0?
for storage, you don't have to raid them. for faster read and write...do the RAID 0,..for mirroring..do the RAID 1
heres more info on raid setups.
i have no clue on your video card cooling,..others here will probably have an answer for that.
as for keyboards,..anything with the logitech brand is good.
for putting them together here are the basics
for part 1
for part 2
as for other peripherals,..like the cooling,..once you get everything installed/ put together,...i have doubt that you can do it as well
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