
How long you're intending to keep "basic" components (CPU/mobo) and are you much into heavy overclocking of everything?
And in normal home uses 1TB Samsung F1 and WD Caviar Black are practically equal to Raptors so I don't see benefit in paying that much more for much smaller capacity.
sell your 4850 and get a good single card
Run two of these in RAID0 (£90 less / faster / far quieter).
VelociRaptor is 110MB/s average read in this test:Would they be quicker in RAID0 than the raptor then? Never ran a RAID setup before but I know my raptor is far far quicker than any 7200rpm drive I've tried...
crap access time tho so loading into games will be pants and it only just beats a single raptor
sell your 4850 and get a good single card

id seriously reconsider the velociRaptor.
far too expensive and if the normal Raptors are anything to go by, will be the loudest thing in ** case no matter how you try to dampen the sound.