Couple of features that would be nice to have for the notification icon:
“Show Online Stats” as a rightclick option, like we used to have with the pre-2.0 versions.
When the client is first started, a pop-up (like the “Pulse Successful!” one) if you’re not logged in. It’s happened a couple of times that I’ve booted up and not checked WP until a few hours later, and it’s not been logged in at all.
Or perhaps just an X covering the icon in the tray to keep it simple.
Also, another nice idea would be to have a link to these forums in the “Account” tab of the client - might get some more people giving feedback if there was a faster way to get here.