Anyone seen "The Big Kahuna"?
Kevin Spacey has a line it that I always reference when people discuss the makings of a good actor. I can't quote it exactly, but it's like "Because if you know what you are doing, then you don't have to look like you know what you are doing, because it comes naturally. Like a great actor who looks like they're remembering something that happened to them instead of just saying their lines."
Not enough actors possess that quality. Depp is one of them that does, imo. So many movies he makes, I don't feel like I'm watching a "Johhny Depp movie" so much as viewing a story about the character he's immersed himself in.
There are some actors that simply get type-cast into life long roles, like DeNiro. Yeah he always plays the same basic guy, but I still love the movies. Well, the good ones anyway. >.>
My personal nomination for plank-acting? Ben Affleck.