Gmail notification in Ubuntu's native mail icon
There's an applet called gm-notify that uses the built-in indicator and can launch either Gmail or your desktop mail client. It's not in the default repositories (yet?), but it seems safe enough to install: http://bleedingpaper.com/gm-notify/
Oh, and Empathy is the chat client. I think you meant Evolution :)
I use Gmail Notifier: or try to go in Applications -> Add/Remove (or Software Center) and then type in the search box "gmail".