well there's 2 things you need to think about, do you want to secure your wallet or your whole pc/mac/linux system?
securing your wallet, use the password lock at least (doh), better still stick your wallet on a usb drive (even one of those password protected devices) so there's no wallet on your machine at all until you mount the usb drive. keep backups on a 2nd usb drive as well.
i would never use cloud backups but if you think it's ok, encrypt the wallet, stuff it in an encrypted rar file as well (paranoid? put #1 encrypted rar inside a 2nd rar). and then use more than 1 cloud.
securing your system - truecrypt whole system encryption (windoze only) is the best way to go.
or there's a way of doing it for freebsd systems as well (via geli, google it).
linux i dunno, i only used *bsd.
if you're in the paranoid security department, put your whole encrypted OS on a usb drive so there's no bitcoin software on your main machine. keep a backup of course in case the usb flash runs out of write cycles.
all imho of course