I'm thinking of reconfiguring my drive set-up in my Mac Pro after watching my MBAv2 boot and load apps faster than my quad 3GHz! I was thinking of the following set-up: Bay1 - 300GB Velociraptor (System Drive) Bay2 - 300GB Velociraptor (My User) Bay3 - 750GB Baracuda (Data) Bay4 - 750GB Time Machine Back-up for Bay1 Bay5 - 750GB Time Machine Back-up for Bay2 Bay6 - 750GB Time Machine Back-up for Bay3 Bay5 & Bay6 will come into existence with MaxUpgrade's optical disk mounting accessory. I mostly do scientific computing on relatively large files (100MB to 2GB). I don't need excessive drive speed, but I think an upgrade is in order. I also get page outs with 6GB of ram so that will get a bump too. RAM is so cheap these days. I think I paid $600 for 4GB ~1.5 years ago. Anyways, I already have the 750GB drives so the costs is really just the two velociraptors and the optical mounting system (totalling ~$750), but this isn't too far off from the price of Apple's RAID card. So which is better? 4x750 as RAID5 or the above. I should point out that everything will be backed-up to an off-sight server too so that isn't currently a concern.