Classic Gnome fans, fear not. You can still use standard Gnome in Ubuntu 11.04 if Unity is not your bag.
To change to traditional Gnome, logout and then after clicking on your username, select Ubuntu Classic Desktop at the bottom of the login screen.
Enjoy the latest and greatest Ubuntu with regular Gnome!
Edit! Alternate method:
Click the Power icon > System Settings
Find and click on Login Screen where you can set your default session as well.
Edit2! Or why not try KDE:
Install KDE with:
$ sudo apt-get install kubuntu-desktop