My first vote goes to Simplenote (
http://simplenoteapp.com/) - it's an app I use every day and it impresses me every time. It does exactly what it says, takes simple text-based notes, but coupled with desktop app. Notational Velocity (
http://notational.net/) these notes are synced over the air between iPhone/iPad and desktop/laptop - no docking required.
Vote #2 goes to DropBox, for much the same reason. PDFs of documents etc.. go into DropBox so I have a copy of the original, and the text is pasted into Notational Velocity > Simplenote for editing if required, and that's it - almost everything I need in one place!
Still looking for an app that will let me add text boxes (e.g. dimensions) to a drawing; Pages does it, but the files it produces are pretty big to be DropBoxing over 3G. Lots of drawing/note-taking apps out there, but haven't found one I like yet, so any recs gratefully received!
Cheers, Pete