Feel free to use RAID0, it'll be awesome.
However, while you run it you need to feel comfortable with the idea that if it suddenly got wiped/caught fire, you wouldn't lose anything significant (except time spent rebuilding it).
Spend the money on a backup system. Make it take regular snapshots or whatever, of all important data, on all your drives. All platter-based drives are subject to failure (Hell, I had one on my backup device fail last month!), so always behave as though it is just about to break.
Seriously, HDs are cheap and backup is easy. Do it. And go Raid0 on your main drives and enjoy the speed AND peace of mind!