StartCleaner

StartCleaner at work
Here you see the Windows XP Temp folder being cleared of old files that were not cleared by Windows at Shutdown.
By putting a shortcut to StartCleaner in the Windows Startup group you can win back precious disk space everytime Windows starts.

Setting up StartCleaner
The Windows Temp folder is added automatically, but you are free to add as many other folders and filemasks as you like.