Count me as one of those junkies! But my iPod has some catching up to you with yours. I'm roughly 4,000 behind you.
The playlist capability, and especially the smart playlist setup, is one of the best functions of that little device.
For example, I have several full-length operas on my iPod but I don't like some random aria popping up when I shuffle my music. So I just create a Smart Playlist that blocks all classical music. I also have a Smart Playlist that plays nothing but songs with 4 or 5 stars in the Rock genre and a Smart Playlist that only plays pop music from the years 1974-1979.
The combinations are endless.
Now I'm loading all the album cover art into iTunes so when I upgrade to the 60GB photo, I'll be ready.