Wow, thanks for posting this! I downloaded the iWork/iLife apps because they were free, but if I'm honest, I doubt I'll ever use Pages/Numbers/Keynote on the iPad. Now that I know those three alone are collectively using 1.2GB (and another 664MB for iMovie) I'm getting rid of them ASAP!
The number one storage hog for me is Pocket Casts, but I download a ton of podcasts (both audio and video) for my commute.