I had major problems with the final 5 minutes of TDK. A) Batman isn't supposed to kill, especially an essentially good man like Harvey Dent, who had only fallen to the Dark Side in the last week (?) or so of his life. In doing so, the Joker basically won - Batman broke his "one rule." I think Bats should've figured out another solution. I was much more interested in Joker than Two-Face, so the showdown with Harvey seemed anticlimactic to me. C) It was just too "clean" that Batman was going to be blamed for what Dent did. Again, Joker's prophecy comes to pass: The public turns on Batman. Brilliant in some eyes; convenient and contrived in mine. D) Gordon's son: If Batman saved my life at that age, it would take a lot more than Dad's frilly speech at the end to prevent me from blabbing nonstop to every friend/teacher/acquaintance about what really happened that night. I'd call the papers if I saw everyone calling Batman a killer, knowing what had actually happened.
Despite the ending, I do love the movie, mostly cuz of Joker/Ledger.