Everyone knows who Ben Affleck is. If you didn't know who he was before Jennifer Lopez, you knew who he was afterwards. There's probably a lot of people out there who, after all that publicity, were more familiar with Ben's romantic life than they were their own.
The downside of Ben Affleck is that he's constantly being cast in the same role in his bigger movies, and carries the same personality from film to film. Strangely, one of the best performances Affleck has given in recent years was in Surviving Christmas, a film that seems to have been almost universally panned. Affleck's portrayal of the desperate, neurotic and incredibly annoying Drew Latham rings true.
An actor reaches his pinnacle when he can make the viewer feel for the character, be it extreme love, extreme hate, or even pity. Drew Latham was a character to be pitied, because by the end, viewers could actually see his side of things. This is as opposed to almost every other Affleck film, where there is so little personality for Affleck's characters that, in most cases, his character could disappear altogether and viewers would neither know nor care.
That said, there is part of the film world that Ben has basically avoided up until this point -- playing the bad guy. He's been a bit of a jerk in a couple of the Kevin Smith films, but he's never started bad and ended bad -- real, real bad -- in any major film. He's always misunderstood, misdirected, or what-have-you. Affleck's success in playing the jerk indicates that he may be able to play a bad guy to perfection. Look at John Travolta -- when he's good, he's very very good, but when he's bad, he's so much better.
Perhaps that can be the next great thing we'll see from Mr. Affleck -- him playing the ultimate villain. Until then, unfortunately, he'll always be a mediocre player in the Hollywood world -- one who isn't given the meaty roles, and one who the public will never really know if he can handle them.