I sold my iPad 3 and just have a MacBook Pro right now. I mainly used it for browsing, gaming, music, videos, etc. I also used it for note taking at meetings, etc. However, it was my main computing device at that time. I've recently purchased a MacBook so my need for the iPad sort of decreased. But I still love the idea of having a place to store my music, video, games, apps and be able to take pictures/video too. I could go with either the Mini or iPod touch really...sort of comes down to how portable of a device I want. I like the thought of always being able to have the iPod with me (particularly since it has a great screen and camera now).
There is really only one application that is iPad-specific that I really liked and that's Notability. However, the dev said they were working on a iPhone/iPod touch version as well.
Space is certainly an issue as 32GB is the absolute minimum I would go with an iOS device. 64GB is nice and that's why the Touch is appealing now.
I'm really curious how the screen for the Mini turns out. It likely won't be retina so that's a knock against reading (wouldn't be a problem on the iPod touch 4in screen).