I love dropbox--I use it to share between my linux laptop and windows desktop--but I don't want the full implementation on my N900--I don't want all of my files constantly syncing on the phone. I would like to see some kind of selective interface that lets me browse, download, upload, etc.

My favorite use of dropbox, by the way, is that I keep a Keepass file on it. I can access all my username/password combos from either computer and keep it up to date as needed. And I download the file to my N900 using the dropbox web page so I always have the passwords on the go. There is a KeepassX app for the phone that works well, though it is not optimized for the small screen.