Gerard Butler's character...
...was much more sympathetic than Jamie Foxx's, and I think Butler should have won in the end, or they both should have lost. This movie would have been so much better with a 'Se7en'-esque ending.
Just my opinion, but seriously, Foxx's character was not a hero--he was a bad lawyer, he was arrogant, he was condescending, and he showed very little remorse for his poor judgment. But he wins in the end?! (I'm supposed to be rooting for this jerk?!!)
Now, Butler's character definitely went full psycho, and deserved to be punished for his actions, but I never really bought the ending where Foxx outsmarts him. If anything, they both should have gone down.