Dropbox is pretty popular, so I thought it was worth mentioning that Dropbox has released version 2.0 of their software. Version 2.0 brings a number of UI changes, most noticeable is the drop-down menu pictured above. The new interface makes it much easer to share files and see your recent changes.
As far as I can tell, Dropbox doesn't notify you of a new update, so you can snag a copy here. Available for windows and Mac!