You can select the viewport and when you rotate it the view rotates with the Viewport.
With the AutoCAD 2010 based products we have added the ability to rotate objects in a viewport with the viewport easily without having to become a UCS ninja master. This was a top item in the AUGI AutoCAD Wish List June 2007 submitted by Bill N. AutoCAD customers have been asking for the option to rotate the view with their associated viewport.
