Put Linux on another partition and only use it for the Bitcoin client.
*writing windows virus that reads ext filesystems*the partition could be on a USB memory stick so you could remove it and lock it in a fire proof safe
even if you got the wallet.dat file you need to decrypt it.
people get hacked by downloading another program (like mining software) that key logs their password.
I like this idea a lot. I'll split it all up among a few wallets and store the bulk of it on an USB. Or is it best to sell while the cost is so high.