I've just moved into a WIN7 / Autocad 2010 environment and I'm experiencing the same thing when MAXIMIZING the ACAD window.
Also the ACAD session (when MAXIMIZED) covers the Start Bar (set to Autohide) so that you have to use the Windows key to bring it up. Quite annoying as I miss Communicator msgs or any other program that might need attention.
WIN7 Pro SP1
Intel(R) Xeon(R) CPU E5603 @ 1.60 GHz
6.00 GB Ram