Well, a shuffle and a nano is easy, just with music. My nano has only a very small subset of my music, plus a couple of iPod-resolution photo albums.
I have a 30 GB 3G iPod (black and white screen, music only, no photo, no video,) that is a little over half full. (I have 15.82 GB of music, not counting Music Videos.)
If I had a photo-capable iPod, and turned on 'Include Full Resolution Photos', I would fill up a 60 GB iPod Photo. If I had a video-capable iPod, I would fill it up with music and video, without even including full resolution photos.