I have a 15 gig iPod. My primary goal was to put every Thelonious Monk cd I have on it and now I've got 1.7 days of Monk stored (5.59 gigs). I used the highest bit rate (320) and with some Sennheiser headphones, everything sounds pretty good. And using the smart playlist option, I have some fun playlists like 31 versions of Epistrophy running from longest to shortest. I use the Griffin iTrip to listen in the car and in bed on my Bose Wave Radio. (I think my right channel audio input in the Bose is damaged and I get some odd sounding performances when I use cables and the dock for the connection. The cables sound better than the iTrip but the iTrip is still decent enough.) I have my only Mosaic on it - the Horace Parlan (and it appears as if I've lost disc 1 of the Carmell Jones Select). And lots of Tina Brooks, Sonny Clark, and Red Garland.
I read the Newseek and desperately want the new 40 gig iPod - but I'd need to add an external harddrive. And that's too much work for now. I'll wait until I but a new computer.