Music Library
The thing about carrying around your entire music library is that not every song on every CD is worth listening to, again and again. And the reason many of us grab an iPod is so that we can listen to what we
want to, versus what we
can. I just got my iPod this week, and went through my entire cd collection looking for songs to put onto it (FYI, got about 300+ cds, more than enough to fill up 5GB) and after going through every CD, I've got about 380 songs at ~2.2gb worth (I encode at max freq + have a lot of 10+minute songs). Granted, a lot of my cds suck, thanks to my whimsical buying tendencies

, but hey, the point is that you have more than enough room to listen to your favorite songs.
When 10GBs comes out, I'll be psyched like the rest of you (and hope there's some sort of upgrade route, official or unofficial) but for now, enjoy your 5GB! If you don't learn to appreciate what is there, you'll never be satisfied, even if they threw in 20GB (by then there might be quicktime movie files or what have you, and you'll want to copy your entire video collection and 30terrabytes just isn't enough! Well, you get the picture....

)
btw: Mischief, supposedly there is a way to boot off the iPod (
http://www.ipodhacks.com) but it's not recommended, since the iPod's drive isn't meant to handle the same stress and use levels as a regular hard drive. I've read that someone used their iPod as a OS X Server, but fried it after a few days (or was it hours?) since there's no heat regulation, and it was just too much strain to handle. I think it'll be hard at this point in time to get full FW hard drive capabilities on something so small, but yeah, it'd be sweeeet if they could do it!