TIS, I share you're surprisedness (is that a word?)
DiCaprio played in a couple of non-commercial well-done movies as a boy (Gilbert Grape, Basketball Diaries) in which he wasn't bad, then made his breakthrough with Titanic (not a bad movie, but only the true romanticizers (again, is that a word?) would think he's responsible for that) and after that he had some guts starring in The Beach, which was a positive surprise to me too.
Off course he's a spoiled kid when only in his early twenties or something, but his acting nor the movies he played in can be really called bad. Now, for this winter, two crime/gangster-films with DiCaprio, this could mean his "second breakthrough" if you ask me. I'm looking forward to another historical epic with an Irish DiCaprio, and off course the Spielberg-Hanks-DiCaprio movie "Catch me if you can".