This subject it just such a no brainer.
Get a big hard drive Internal HD for Primary Data
Get another big internal HD
Get a big external HD
Use MirrorSoft to back up primary HD in real time to internal & external HDs.
when you leave the house, take external HD or put somewhere "safe".
Always backed up on two HD locations. In real time. Never worry again about HD failure.
My next HD purchase will be one of the new LaCie 1 TB units.