This is just experimental, but seems to do more than FMenu does, for example it offers the ability to post status and allows for Growl notifications. It does not summarize your last few Wall posts or news feed items, however (which would actually make Facebook useful rather than annoying).
If you’re on a Mac and you use Facebook frequently, you’re going to love this. We’ve stumbled across a new experimental application being developed in-house at Facebook that’s called “Desktop Notifications“. It’s exactly what it sounds like — the application sits in your menubar at the top of the screen, giving you easy access to your News Feed, recent Wall Posts, and messages. It appears that the application is open for anyone to download (though it’s only got a few dozen fans so far) but note that Facebook is clearly labeling this as a prototype and experimental, so don’t expect any support if something gets messed up.