RAID 0 does rock when it comes to speed but then again it is only as reliable as the weakest drive in the array. Yea know, like the weakest link in a chain........it only takes one!
I use to have a 5 disk RAID 0 running in my machine, then one day I powered down my system to do a modfication on my video card. Put the card back in and started it up........... Drive #2 dead! &^$%!!! Luckly I was smart and had all my data copied to another HDD in my server. I dont mind so much that the drive failed (because of my backups) but I did mind the time it took to reinstall my OS (I dont believe in backing that up unless it is a PERFECT copy) and then copying all my data back onto the array. Hence the reason why I decided to go with RAID 5.
I also discovered that you really dont loose THAT much performance with RAID 5 vs RAID 0. A (3) disk RAID 5 preforms almost just as well as a (2) disk RAID 0 and writes take just a bit longer. If you get a card with a decent cache module on it, then the difference is almost null.
BigBen: Here is what I say..... if you want flat out speed and really dont care too much about space, GO SCSI. If you want more space and are not too concerned with speed, GO IDE/SATA. If you want reliablity (and speed), GO RAID 1 SCSI.
Done!