I can't really say who is the best actor or actress as some actors have completely different styles and roles.  There for comparing Adam Sandler to Matt Damon would just not work because Adam Sandler excels in Comedy where as Matt Damon is a diverse actor etc.

Anyways I'd take Angelina Jolie for her diversity

Salt
A Mighty Heart
Kung Fu Panda
Mr & Mrs Smith
Changeling
Lara Croft

Sandra Bullock and Julia Roberts are also amazing actresses themselves.

As an actor I'd take Leonardo DiCaprio.  Everything he is in he accels in.

Django Unchained
The Departed
Titanic
What's Eating Gilbert Grape
Catch me if you can
Inception
Blood Diamond
Shutter Island

Other great actors that i had in mind was Tom Hanks, Will Smith, and Matt Damon.

Anyways what are your alls favorites?

Tom Hardy is a rising star for sure.

Bronson
The Warrior
Inception
Tinker Tailor Soldier Spy
The Dark Knight Rises

One thing that people really like about him is that he like Christian Bale can go through drastic body changes and on top of that his acting is top notch

I don't know what it is about Angelina Jolie, but just looking at her makes me want to punch an orphan in the face. 

For actresses I would have to go with either Natalie Portman, or Jennifer Lawrence. Portman has a better track record, but Lawrence was just incredible in Silver Linings Playbook. A few more performances like that and Lawrence will be my fav for sure.

My favourite actor is tougher to choose because I'm a fan of so many. 

Russel Crowe because of Gladiator and L.A. Confidential.

Dicaprio for all of the movies you listed.

Daniel Day-Lewis might be the best villain ever. His Bill The Butcher from Gangs of New York in particular was really great, and his performance in There Will Be Blood was also right up there.

Joaquin Phoenix is good in just about everything he does. His portrayal of the Emperor in Gladiator was top notch.

I guess if I have to choose only one it would be Russel Crowe even though he hasn't done much lately. He had a run from about 1997-2005 where everything he did was great. 

Johnny Depp - I seem to love all his movies.

Leonardo DiCaprio - Same here.

Awwh that was kind of mean :/ lol

Marlon Brando

Katharine Hepburn

Gary Oldman is my favorite actor because he's fucking incredible in everything, and Eva Notty is my favorite actress because women can't act.

Dont know about best but my favourite actor would be Leonardo Dicaprio.
My favourite actress would be Hilary Swank.

Denzel Washington is awesome. As is Keanu Reeves. Hard to say which one is the best. About the best actress, I would have to say Alexis Texas(it counts, right?).

I'd also add Morgan Freeman and Jack Nicholson. Actresses i'd say Ellen Paige.