Here's one way to get immediate benefits out of Ubuntu One: use it as a conduit to synchronize Tomboy notes between one computer and another. Tomboy's synchronization files are simply XML, and you can specify which folder they're in.
Do the same on as many computers as you use, and voila! No need to separately organize your notes on different computers.
Update: I've tried this but it works only up to a point. Unfortunately, Ubuntu One will sometimes decide that there's a conflict in your documents and write that into a new file name that has the word "conflict" in it. Anyhow, use with caution.