Mac the Knife,
your exactly right about problems with power surges and theft, An offsite backup is a very good idea.
Of course, It all comes down to cost - How much is your data worth?
Imagine losing every single item on the PC, If that gives you cause for concern then look at a decent backup system, A DVD writer can be bought for around £250 (
http://www.autdirect.co.uk) and offsite storage can be very cheap - I use my desk drawer at work!
The removable drives are a godsend, I use them all the time as it makes it so easy to remove and swap disks around between PC's. (Again, All my stuff is bought from
http://www.autdirect.co.uk - Good Prices).
A safe is a good idea but remeber that they may well be fireproof but they are not heat proof. I remember a scene very well from a few years back - A client's premesis had burnt down and they finally were allowed to dig the safe out of the rubble (It fell through five floors as the floor supports burnt through).
The safe was totally intact, Not a scratch or dent, The key was produced and the safe opened to reveal the lovely site of 100+ backup tapes and CD's turned into one huge molten mess - The safe had acted like an oven a cooked the media inside it.
Another client got lucky when they tried to restore a single file and found that every single tape they had was blank.... In two years they had never done a test restore.
As soon as they realised they made bloody sure that the backup job was modified to backup the data!
Good thing too as two weeks later the mail server died......
Gary.