I've found that some of the tools I discovered in 23 Things but didn't get that excited about, have suddenly become much more useful now I'm using the tablet, in particular Evernote. The interface on the mobile version is so much nicer than the rather dull PC version (see right), and it's very intuitive. I'm using it for my lecture notes and quotations I want to put in essays, nothing too fancy, but it's working very well. I could have used Google Docs for the same thing, but I find editting Google Docs quite fiddly on the tablet, even in the app version.
I think I still haven't taken full advantage of Evernote yet, as it has all kinds of things like OCR for images and handwriting, and I discovered entirely by accident in my last lecture that it has a recording feature, and my tablet has a microphone, so I could have recorded all of my lectures as well as taking notes. So when I get a chance I really need to sit down and explore all of the features I don't use, because some of them are probably very useful!