I've recently upgraded from 10.10 to 11.04, and immediately switched to unity-2d (running on a netbook). Then I tried to load the 10.10 panels because I didn't like the globalmenu. After rebooting I ended up w/out Unity and w/out Gnome. Alt+F2 doesn't open terminal either, and I can only access the browser thanks to a keyboard shortcut I once set up. How do I resolve this mess..? When I logout/login it doesn't let me choose between settings (ubuntu classic, etc.).
Thanks!

nano /home/YOURUSER/.dmrcand change the Session entry to Session=gnome-2d. Press Ctrl + o, Enter, Ctrl + x. Now runchown YOURUSER:YOURUSER /home/YOURUSER/.dmrcand reboot. You now should at least boot into a classic GNOME session. – htorque May 7 '11 at 21:17