Yes. I have a 30GB iPod, 20GB prior to this one, 20GB prior to that. I typically fill them up but not with music. Usually I have about 5 or 6GBs of music on my iPod, the rest is either photos or files, mainly files, that I am transporting to the studio. 30GB seems plenty for now, I don't keep my whole history on there just the last few projects and my portfolio, which is saved as movies so I can play them.
My wife works in a similar fashion except that her iPod is more like her main drive, center of work, she doesn't store stuff on the computer.. only backups and working files but always copies back to the iPod.. so she has also filled hers once or twice, all depends on the current projects.