I've gotta say that it was Perfect Dark Zero, Resident Evil 5 or Fallout 3.
Okay, Fallout 3 isn't THAT bad, but it's dull. Really, really, really dull. I explored every freaking where because I thought I'd be discovering cool new areas. Aside from a small mountain section, everything looks the same. It's all brown, and what isn't brown is gray. A post-nuke zone doesn't HAVE to be brown. It doesn't. Brown enemies set against brownish-gray buildings in a tannish-brown world. Good luck finding enemies without hammering the right bumper constantly.
On top of that, most of the missions are fetch quests. Oblivion had plenty of those, sure, and Fallout 3 is similar to Oblivion. But you know what Oblivion had? Freaking variety. Pick a guild, or some quests to do, and just spend all day doing quests. Every town had like a billion quests, most of which were pretty unique. Many of them didn't involve combat at all. Oblivion does everything better than Fallout 3. Also, Fallout 3 is AT LEAST as buggy as Oblivion, if not much more so. I personally encountered friggin' loads of game-stopping bugs in Fallout 3, as opposed to a mere handful of possible glitches in Oblivion.
RE5 is just baaaad. Bad story, bad controls that the game won't let you customize (yeah, way worse than RE4), bad AI, bad partner nonsense, bad horror, bad enemy designs... Bad everything. It's kinda fun in a cheap, sleazy, popcorn action blockbuster way, but it's still bad.
Perfect Dark Zero is so aggressively mediocre it insults every one of the five senses. Nothing works very well, and many things just plain don't work at all. Say what you will about modern gaming, but cheap, crappy stealth levels are something that never belonged in FPS games and I, for one, am happy to see modern shooters moving away from them.
Oh, and the PC version of Kane and Lynch: Dead Men deserves special mention for being nearly impossible to freaking run, loaded full of bugs and never patched. I finally broke down and bought the 360 version so I can rob a bank already.