Although I haven't put effort into implementing it yet, I have heard good things about Armory as well.

Until my balances reach a high enough level that I'm overly concerned about losing them, I'm using a USB drive with Multibit installed on a Truecrypt volume as my wallet.  I backed up the private keys to other encrypted volumes on other USB drives in case the primary one fails.  Seems to be working so far, but not the "ideal" solution.

I'd appreciate any thoughts on this approach.