You don't need to transfer the songs manually (huge PITA), you can each create playlist(s) and sync different playlists to each iPod. Actually, having to copy music manually onto my Palm was the #1 reason I decided resistance was futile and became assimilated into the iBorg. 
And, you don't need to copy your music onto your computer's internal hard drive (probably it's a good idea to keep it external, actually). I'm on a Mac, but DH has a Windows computer and keeps all his music on an external drive. On the Mac side, open iTunes, select "Advanced" from the menu bar, and the first option there will be "iTunes Music Folder Location." Then click the "Change" button and browse for the location of your music folder. (obviously making sure the drive that stores your music is connected). I'm pretty sure everything is the same on the Windows side, but if that doesn't work for you, let me know and I'll ask DH when he wakes up 
You will also need to authorize the new computer onto your account at the iTunes Store if you have any music that you bought from iTunes. After you've authorized the new computer, if you're decommissioning the old one, deauthorize it (you only get 5 authorized computers at any one time, and they can add up if you forget to take your old ones off).
ETA: not on point, but another handy hint that not everyone knows about their iPods: you can create a smart playlist (either independent, or a subset of another playlist) that's limited in size and sorted by date last played. That way, you don't have to put artificial criteria into a playlist just to make it small enough to sync with your iPod, and once you've played a song, it scrolls off for a while, and you don't wind up hearing the same songs over and over while other songs never get played.
Last edited by OakLeaf; 12-13-2008 at 06:55 AM.
Speed comes from what you put behind you. - Judi Ketteler