I was just about to post that! I don't need 40GB, though. I have barely used 1 on my SD and MD combined currently.
I've been playing with encoding video to play on my n800 and zaurus, so that I can strap one to the headrest in my car and let my son (nearly 4) watch videos on a long journey, and at any reasonable quality a ripped DVD is 100's of MB, so this 40G is not actually so crazy!
--edit--
or, 40GB would be enough to store pretty much all the mp3 files I regularly listen to, so it'd possible to use any Z (7xx,8xx,1000,3xxx or 6000) as a damn good mp3 jukebox especially in the car! my previous idea for that was to get a wireless NAS (Asus made one) using wireless with ad-hoc for a file share of 80GB drive of sounds, but suddenly you need no external drive!