"Move_objects on"      "Boolprop snapobjectstogrid false" might be useful too.  Oh yeah, don't type the " in the box, just the words
Make sure if you use the grid cheat you change it back to "true" when you're done (boolprop snapobjectstogrid true), or you'll have a heck of a time placing things.  I find this cheat especially useful for coffee tables.  
