LOL at people calling Di Caprio and Depp overrated. Daniel Day-Lewis is among the GOATs though.
Depp is overrated imo. He's good, and he has the ability to carry a film like someone else said, but he isn't some incredible GOAT actor like people think he is. Being quirky and over the top doesn't really make a good actor. Donnie Brasko and Public Enemies prove he's got some chops though, but until I see more of that and to a higher level, I'll continue to think he's overrated, but I do like the guy.
Leo definitely isn't overrated though.
Ben Affleck has to be the most overrated actor.
Affleck is generally considered to be awful, which I actually don't think he is given the right thing, he's very good in his own films (Good Will Hunting, Argo, The Town).
Wahlberg is someone who is just kind of bad in everything though apart from comedies it seems. He was the best thing about The Other Guys and Ted (not saying too much I know, but he showed good comedy acting skills and looked to be having a ton of fun). He was good in Boogie Nights too. I didn't even think he was very good in The Fighter either, he just seems to have to force the words out of his mouth.