What would be better? I would need to buy a RAID controller and they both come out to the same price because I already have a WD500AAKS drive. If i did do the RAID 0 then I would buy the Black Edition that they have out
RAID does not give as much of a speed increase as you may think.
IMO it is not enough to offset the potential issues.
As it looks like you are ready to spend a bundle on a fast hard drive setup, look into a WD VelociRaptor or a small SSD with another storage drive.
When I went from a single-drive to RAID-0, I noticed a substantial difference (all else being equal, and it was an addition to the existing drive, so it wasn't because of quicker drives being used). Do what you want, but if you want RAID, just make sure you have a backup or possibly suffer the consequences of a failed drive.