My friend asked me a while back this and I thought it was an interesting question. xD
Simply put out of the movies you own, which actor stars in the most of them. (Voice actors count!)
Mine are John Wayne (7):
Stagecoach, Fort Apache, Red River, Rio Bravo, The Searchers, The Man who shot Liberty Valance and Rio Grande.
Tom Hanks (7):
Toy Story trilogy, Forrest Gump, Castaway, Saving Private Ryan and Catch Me if You Can.
John Ratzenberger for me. 
I don’t think I have to tell you which movies I own that he’s in.
Same with me. I don’t havea lot of movies in my room, but John Ratzenberger is in every one of my movies that are in my room.
Tom Hanks for me. There are a lot, but he flew straight to mind. I have 7 in my bedroom with John Ratzenberger, and there are 4 of his in the family room, so I suppose he wins.
John R and Tom Hanks! Oh, and Will Ferrell.
This is an interesting question for me because usually, I don’t buy movies because my favorite actors are in them. But without that bias, it’s kinda nice to see that John R is the one that appears the most.
Let’s see…Tim Allen. I own two movies he is in: Toy Story 3 and Santa Clause. I think Santa Clause is boring, so I put it in my Toy Story 3 DVD case which has a hole in it.
EJE: I love Will Ferrell! We have a lot of his movies, but I don’t count them because they’re my dad’s DVDs, not mine.
Nearly added number 8 to Wayne’s list. Very nearly bought ‘The Green Berets’ but didn’t and save my money for another day.
And for Tom Hanks, watched Saving Private Ryan against last night for the time in yeeaaars.
WOW. Nuff said. Forgot how good it was. One of the easiest 10s (out of 10) i’m ever ever going to give.
I can totally agree with this. Spielberg is the master.
Tom Hanks; unless you count Ratzenberger.
-And it seems many of you have the same ordeal. 
John Ratzenberger
John Ratzenberger, Kevin Spacey and Michael Cera-Ceraaa 
Heehee, Michael Cera is awesome, even though he plays the same character in every movie!
Ha, Not as bad as Jason Statham. the amount he plays the same charcter near enough is ridiculous, literally in every single movie for the past decade or so.
John Ratzenberger for me as well… 
Yeah, well, there are so many actors who are like that… We could actually make another board just for that
I love Michael Cera 
But it wasn’t until I skimmed through my DVD’s that I realised I had so much of him playing the same character. He even managed to make Scott Pilgrim the same character as Paulie from Juno. That’s just funny.
Heehee, I’m a fan of his as well! Especially in Juno and as Alexander Hamilton in Drunk History.
And he was great in Nick and Norah’s Infinate Playlist