Click on the Ubuntu Button (in the top-left corner) and search for CompizConfig Settings Manager and open it up.
There scroll down to Desktop section and look for Expo and click it. Click on the Expo key's key-binding and uncheck Enable. That will disable the expo feature. You could also alternatively assign a different key-binding to it.
Sorry for very late reply..busy with wedding stuff :) – javanoobSep 30 '11 at 2:14
@javanoob no problemo :) – nitstormSep 30 '11 at 6:08
I have the same problema that javanob in the beginning. On Ubuntu 11.10.
I have changed it as nitstorm says and the behavior is the same. Im changed the shortcut to Super+e and then, when y stroke Super+e start expo and if i use Super+s makes the same thing (start expo).
I'v assigned Super+s key to open synaptic on Keyboard shortcut settings but always start expo plugin. Thanks, – user53367Apr 3 '12 at 23:25