The biggest pain in the ass to move for me was the 2-gun Aerosmith Revolution X cabinet. Goddamn it, that machine sucked. We managed to get it stuck 3 different times in my stairwell, then couldn't stand the thing up without aligning it to tilt up into the recesses for the flourescent lights in my basement. My ceiling is plenty tall enough, but since the game was oblong it was hard to tilt it upright without that extra space.
Thanks for all of the suggestions for tools and sliders. It's a pain in the ass to slide to clean behind it, or get in the back.
After the Aerosmith debacle I realized how easy I had it when I moved my Q*bert into the basement.
So goes the hobby, I suppose.