Gnome Main Menu, a start menu applet, comparable with Kickoff for KDE, has a little Brother: Gimmie.
I have no special preference, they are close relatives and both likable.
If you are Using Feisty; both are available, make sure to have the universe/multiverse repositories set up.
sudo apt-get install gimmie gnome-main-menu
Here is a screenshot of Gimmie:
A screenshot of Gnome Main Menu: