Me too. He’s awesome, and you don’t feel like you’re watching “A Gary Oldman Movie”, since he’s able to play vastly different characters in so many movies, so you’d still have a lot of variety.
My gut reaction is Jack Nicholson. My second gut reaction is Meryl Streep.
Buuuuut…since this is for the rest of my life, and I’m a youngun, I should logically have someon else. Someone younger, who will have new stuff coming out for at least a decade more.
Like Paul Giamatti. 
Johnny Depp, easily.
He’s had brilliant movies in a lot of different genres, he plays really diverse characters, and he usually (but not always) chooses fairly offbeat films to star in. Most importantly, I don’t think I’ve ever been bored by a movie he’s been in. Let’s take a look at some of his films:
Edward Scissorhands - amazing, both funny and genuinely moving
Ed Wood - unforgettable portrait of the finest bad movie director ever
What’s Eating Gilbert Grape - a very well-acted family drama with unique elements
A Nightmare On Elm Street - one of the classic horror movies
Platoon - considered one of the best war movies ever
Donnie Brasco - fantastic gangster movie
Fear & Loathing In Las Vegas - a brilliant, highly literate acid trip adventure
Chocolat - a sweet, well-received romantic comedy
Pirates of the Carribean - a dark, swashbuckling award-winning sea adventure
Charlie and the Chocolate Factory - a great screen adaptation of classic children’s book
Sweeney Todd - a great adaptation of a horror/comedy stage classic
Look at the range, and how they’re all good to outstanding films. And there’s still a lot more in his filmography to choose from.
Tim Roth has had an amazing amount of different roles. And he’s been an actor/ director long enough to have a portfolio of work to last.
Mr. McGregor without a doubt. In fact, I am working on that right now. I’ve watched 18 of his movies in a month, not to mention interviews. He can do no wrong in my humble opinion.
I’m beginning to think that I need therapy.
I’m surprised Denzel hasn’t gotten more traction.
Irene Dunne
Tom Hanks
Morgan Freeman
Tim Robbins
Kathy Bates
Jessica Lange
Meryl Streep
Kate Winslet
Who was the actor who starred in Night of the Living Zombie Threads?
Morgan Freeman’s my man. While he’s not a headliner in some of the movies he’s got a ton of movies to his credit.
Jason Statham would be another favorite but gotta mention Bruce Willis too.
Gene Hackman
Have to say Bobby. Bobby De Niro.
THE CONVERSATION was a masterpiece, and APOCALYPSE NOW is a classic just like AMERICAN GRAFFITI is – and adding the original STAR WARS trilogy to the story of a Jewish-looking guy who punches out Nazis makes it hard to beat Harrison Ford even without factoring in a ton of other stuff.
Buster Keaton.
Tell the Dr that you have a recurring dream… something like ‘Peter Rabbit’… except that in this version, you’re the rabbit Farmer McGregor catches…?
~d&r~
Walter Matthau. Wide range of excellent films. And “Earthquake.”
I think it interesting that by a large margin people are choosing actors rather than actresses.
No zombie actors?? 
I can’t believe no one’s said Patrick Stewart. I’d get some Start Trek, plus X-Men and a lot more to keep me busy.
God, I hate zombie threads.
Boris Karloff for me. I love me Boris.
But Cary Grant would also be an excellent choice. His Hitchcock movies were much better than Jimmy Stewart’s (except for Rear Window).
With Paddy Stewart, you also get the I, Claudius series.