I've occasionally used my iPod to transport photos. I use the £19 camera adaptor. It does the job, although it's not as good as a dedicated photo-vault-thingy.
It would be nice to be able to see RAW files – perhaps this may happen one day.
I also regulary use it as a portable hard drive to transfer layouts from work to home and have occasionally used it as a voice recorder.
Oh yes I sometimes listen to music on it as well