Command key is defaulted to work as expose'

[moved2mac]

I switched to mac on the Inaguration day.
I have gone through the tutorials of mac basics.

But i have some issue. The Left Command button when pressed is working as the way the expose' works. I want to use this command button for executing various other commands. But when i click on this Command button the screeen is shown as thumbnails and i was not getting the desired function the Command button..
How can i change this..???

 

[r.j.s]

System Preferences > Expose and Spaces ...

 

[moved2mac]

System Preferences > Expose and Spaces ...

I just went to the screen you have shown. Its all same as the one displayed. BUt the left command button is still working as expose' functinality even though i haven't mentioned it to do so anywehre in the configuration..