Considering that once you count the combo it's $27 more ($15 normally, $12 from the combo), I think the X3 is better. There was some research done here at Tom's on how the nubmer of cores of the CPU affect gaming that found that going from 3 to 4 cores actually decreased gaming performance. Not only that, but the X3 can have a fourth core unlocked.
Since you're a gamer, I would consider this combo with the X3 and a better board
first. That board will allow you to add a second GPU in Crossfire for better gaming performance.