Why all the hate? Backlash from Titanic, which of course is very overrated. Its actually a pretty decent flick, mostly the second half, but because it was upheld as this amazing piece of work at the time, it was all blown way out of preportion and so of course everyone backlashed, and in retrospect it was very unfair. Its not unlike what happened to TPM.
DiCaprio hasnt done SO much considering that Titanic is nearly a decade old now (gasp! where did the time go?) but he has still appeared in some movies and has proven himself to be a very gifted actor--both before and after that silly boat movie. I mean Basketball Diaries, What Eating Gilbert Grape, Marvin's Room, The Quick and the Dead, Catch Me If You Can, The Aviator. He's had a lot of really good movies, and even his worst ones, Titanic and The Beach, are actually quite good films with pretty decent performances.
People who hate him dont hate his acting ability, they hate his reputation as a heartthrob, and really its only because of Romeo and Juliet (a pretty interesting flick) and that one movie from 1997, which is actually not that bad. He hasnt had any other "boyish" roles since then because all the teenage girls went nuts. He's very underrated.