It's worth mentioning that the ability to actually edit documents requires the paid licenses for the Documents2Go suite (Word2Go, Sheet2Go, etc), but it's pretty cheap (I think $10 for the whole package?)
Otherwise, if you're usually online, you can just get gDocs from the Market and then create/edit your files on your device and save them to your gDocs account.
I'm currently using uiNotes for note-taking, and it's pretty clean. Very little formatting, but if you put the device down and use two fingers to type, you can move pretty quickly. I'd also consider getting the Tape Recorder app from the Market (I think it's $5) and record lectures and dictate notes.