Got the 16GB a couple of week ago. Didn't put much music on (got iPhone for that) so that's only 1GB. Got 2 GB of photos and 1GB of apps. Still got plenty of room to add videos if I'm going away (got the VLC app for that).
So much depends on what you want the iPad for. If I had the 32GB I'd never fill it. Probably only half fill the 16GB at this rate!