u shold never store $$$ on your hard drive, you hard knocks.
Try a brain wallet and use a few clues that you can use to help you remember the brain wallet and store it in several places.
That is a sure way to ensure that no one will ever steal your money.
my brain wallets are as hard as fort knox.
Here is one of my brain wallets. I feel no problem storing my real bit coins in there.
It is as hard as fort knox and it is not stored online or in my hard drive.
If you don't want moey to be stolen, tri using ur brain, dubm fuks.
Different OS doesn't matter that much (I can show you numerous documented security holes in popular Linux distros). What matters is how you care about your data being vulnerable. If you leave your wallet full of money in a car on the street, it doesn't really matter that much if it's an expensive Mercedes or a cheap Fiat: it may be stolen just by breaking the car's glass.
However, there are some uses for lowering the probability of getting hacked. For example, as an additional security measure, one could use a standalone laptop with a totally different OS and CPU (say, PowerBook with a PowerPC CP)U, so that email trojans which use Windows's software vulnerabilities won't work, plus no x86 code won't work because it's a PPC CPU.