AutoCAD 2007 removes the ability to set the snap (and grid) rotation and origin in the DSettings dialog box and Snap command. Their solution? The snap angle and origin match the current UCS.
How inconvenient: I have to set up a user-defined coordinate system just to rotate the grid or relocate the snap origin?
The easier alternative is to use the snapangle and snapbase system variables to change the values from 0 and 0,0, respectively.