For me it would have to be all star batman, it hurt me it was so bad
But... but... I'm the Goddamn Batman!
For me, this is quite tough... I read a lot of crap. The comic I most regret reading/buying was Crossed because it is essentially messed up gore-porn. Other than that though: New 52 Hawk & Dove, Liefeld's standard terrible art, plus terrible characters and story. The fact that this easily beats out Crossed should say a lot about how terrible it is.
Also honorable mentions go out to: Countdown (saved only by Trickster & Piper) & Spider-Man: Brand New Day. And the most recent issue of Stormwatch (saved only by Lobo)
