I would keep multiple backup copies then on different mediums including one offsite (not at your residence) if possible.  You don't have to only keep your wallet on one flash drive.  You can encrypt the files if you want.  For instance have a look at Truecrypt.

Kind of off topic a bit but I believe you show an opening for some commerce.  There should be a site for experts in bitcoin and security to help provide advice for a nominal fee (in bitcoins, of course!).  Have ratings so that there can be a reasonable degree of trust.  This way new users with lots of money at risk could get some personal help and attention on demand.