Fallout 3. I love it, but I hate when it glitches up. Getting stuck in tight spaces, game freeze-ups, the graphics getting all static-y, it could be very irritating.
Modern Warfare 2. This is only partially IW's fault for not testing it on a beta, but most if not all of the blame goes to the online community for turning an otherwise unbalanced multiplayer deathmatch game into a buggy infuriatingly unbalanced multiplayer deathmatch game.
Red Dead Redemption. Played at a friend's house, and it is just full of bugs. Marston sliding instead of walking, weird character model pop-ups ("Weird quantum singularities where men have merged with horses"), black screen freeze-ups, and other stuff.