Not sure where to start with this one.
I've installed Gnome 3 by running sudo apt-get install gnome
on my netbook, it all installed fine and ran fine didn't have any issues with it for a few weeks, then I turned on my netbook and logged in to be given the look and feel of Gnome 2.
I've cropped down the desktop in the image below.
Edit: Pastebinit as requested by izx
Best Answer
Let's try the simple way to fix it first, because that looks like the Gnome3 Classic look (which is, yes, very similar to Gnome2)
Open a terminal, and type/paste:
Logout
Click on the Ubuntu logo:
Select the Gnome session, and click back:
Login and see if you still get the Gnome2 look-and-feel.