I will second this. Many times I have had the game stop when I get in a elevator. Not lock, the character animations still play, I can get to the menus, the doors just don't close and move. Fall through the map: This happens alot, mostly in the Mako. One time I got in the Mako and was launched inside a building (at the two barricades on the planet where you save Liara T'Soni).
Each time I had to quit out and restart from last save. It actually seams to have gotten worse sinse the BDtS patch.