AutoCAD 2005 introduces many new features within in the User Interface which are commonly found and used by everyone. However, there are many people that don't ever use Icon Switches to help aid the startup of AutoCAD. AutoCAD 2005 introduces 4 new switches in this area.
/layout - Allows you to specify a named layout to be displayed when a drawing is opened
/ld - Loads a specified ObjectARX or ObjectDBX file at startup
/nossm - Turns off the Sheet Set Manager when AutoCAD is loaded
/set - Loads a Sheet Set at the start up of AutoCAD
For more information click here to view the Icon Switch PDF file that I have updated for AutoCAD 2005.