The only glitch ive ever intentionally used was the one that made RAAM get stuck behind a wall in Gears 1 on Insane. Seriously, no matter where I stood he either blasted my bandana off or those damn bat-things devoured me (who, by the way had a very loose interpretations of what qualified as a dark area). And Dom had to rush out of cover and die every 5 seconds to complicate things even further. I know that console controllers have limited buttons, but where's the one that tells all your allies to climb under a bin and shut the hell up about the bullet holes in their eyes while the real men got down to some war.
Exploiting glitches online is wrong for obvious reasons, but in Single Player you should do whatever you want to get more enjoyment out of your product.
Also, awesome title.