firstly...
i hated itunes too, but once i got an ipod i succumbed to using it and it is not as bad as i thought. also, every week the music store has free downloads which are sometimes good stuff.
i have a 20 gig, which i haven't had very long and am already almost out of room on. it holds around 5,000 and i'm up to 4,000 something...with STILL not all of my cds uploaded...em...figure out how much music you have and around how much you'd have with cds and stuff.
also, as far as the synching goes...in itunes, you can choose something under preferences or whatever that lets you manually operate your ipod playlist, basically meaning that instead of it automatically updating, you can drag and drop from your library to your ipod. thus enabling you to delete stuff from your hard drive as soon as it's on yer podular device.
this also lets you plug in to somebody elses computer and library, and as long as they have the manually update option checked; you can drag and drop their music to your ipod as well.
i was told when i got my ipod that you couldn't do this, but of course found a way around it and have found that it works quite awesomely.
i am the type of person where, as long as i have my music i will play it in whatever device i have to play it with, which is why it took me so long to finally get an ipod. i wanted one, but they were too expensive...and now that i have one, i must say. i love this thing.
i practically bathe with it.
good luck with all of this mess