Simply backup your wallet.dat before you start accepting payments, and have it in more than one remote location. If you lose a drive on your system you can recover the wallet.dat you backed up at any one of your other numerous locations, restore it, and then after downloading the block chain to that wallet you have your money.
Losing a hard drive can occur at anytime, be it you lose your wallet.dat or you lose your photos or financial data etc.
Backup your data and store it offsite if it's important to you.
Waiting until after the fact is always the worst case.
With a fresh reinstall, I open up the bitcoin program, and viola. 0 BTC.
This is a argument against bitcoin. It would be bad enough investing in something like precious metals or rare coins that could be lost, destroyed or stolen. But this is now the second story I've read about someone that lost money due to hard drive problems.
I'm still lurking and considering. I'm rooting for bitcoin, but stuff like this scares me.
BTW, both of these stories provide good arguments to use a more secure operating system than Windows. Like what? Almost anything available is more secure than Windows. Ubuntu Linux
, Fedora Linux
, OS X
or soon OpenIndiana
(or maybe someday even Haiku