Sounds pretty vague...care to explain a bit more?
Oops! Sorry it was really vague!!!
I would use a Mac OS X based system instead of a Windows based system. And I would try to use internal hard drive (maybe order a 7200rpm) and a Firewire interface.
I agree more or less with everyone, any system can fail. It depends in every work if you can live with it or not (aka if you are paid enough to bring a backup system).