Truecrypt is your friend. Safe enough I'd leave the file lying around on the web with my 36 character password.
+1
infested999,
I use TrueCrypt, however not for my wallet.dat.
This is not because there is anything wrong with TrueCrypt. It is because of wasted space
*.
The minimum size you can make a TrueCrypt container is 292 kB which is more then enough for a wallet.
For a comparison. The average size of a MP3 is 3.5 MB
**.
3.5 MB = 3, 500 Kb (OK... 3,584 Kb, however I think you get the point).
* This is not a consideration for most (if not all) because of the sizes of hard drives.
** See
http://wiki.answers.com/Q/What_is_the_average_size_of_an_mp3_file