This is kind of a tough question, but I'd like to hear everyones thoughts. I'd have to say, as of this moment my favorite actor is John Cusack. I like most, if not all of his films. 

Im not entirely sure I have a favourite, there are many I think do a wonderful job. But when I read the question the first name to pop into my head was Tom Hanks.

He is a great actor, equally good as a voice actor which may sound easy but is actually a lot more work than regular acting as they do tons of takes that never even make it onto the movie, entire days spent making stupid sounds various different ways.

Over a number of decades he has iconic movies; Big, Turner & Hooch, The Burbs from the 80s, League of their own, Sleepless in Seattle, Philadelphia, Apollo 13, Forest Gump, Saving Private Ryan, Green Mile, Cast Away, Toy Story from the 90s,  Da Vinci Code, Catch me if you can, The Terminal from 00s and lastly Cloud atlas, Bridge of spies in the last decade, along with all the Toy Story sequels and the Robert Langdon (Da Vinci Code) sequels too.

I think hands down my favorite actor has got to be Christoph Waltz. His work has never let me down. Even if he's cast in a shit movie, his performance is still on another level... that coupled with how many languages he speaks. 

I have several but today I will go with Jack Nicholson.  So many different roles starting with Westerns, yeah, westerns haha.  Maybe not his best role.  I first discovered Jack in One flew over the cuckoo's nest, brilliant.  Then came  The Shining.  Another brilliant performance.   Another movie I enjoyed was The Witches of Eastwick, fricken hilarious.  Jack does it all.  A true veteran.  This is why I chose Jack today.  The guy is a cash machine haha.  

Johnny Depp and Christopher Walken are two of my absolute favorite ones. I probably have many more, but they are definitely favorite ones. 

Love basically every movie Johnny had been in and Christopher is such an amazing actor. He has a charm that not many people have and a little something something.

When I was younger I also loved Paul Newman. I still do, but haven't seen any of his movies in a long time now. He also had this amazing charm and grace.

Joe Pesci, mainly due to his role in plenty of mafia movies that inspired me in all sorts of ways, his role in The Irishman that stands out to me most in all of them, even though it was past his prime, it just really got me that one especially! 

I dont have any favorite actor/actress because it all depents on what kind of a movie it is 
if it is a horror movie I cant say Angelina Jolie and if its a comedy I want say that Christopher Walken is my favorite
As long as they do it good that do the movie great

I think the undisputed best actor is Leonardo DiCaprio, such a well rounded actor performing flawlessly every film earning that big pay check he deserves, the fact it took so long to win an oscar is crazy.

Best actress at the moment i'd say Jennifer Lawrence, alot because of her off screen presence as well, a very funny relatable person for a multi award winning actress.

To be honest, I think I have many favourites and it changes regularly pending on how active certain actors/actresses have been recently or what I've been watching lately. Due to that, this answer for me could change every month or so.

However, at the moment I'm loving the method man, Daniel Day-Lewis. He literally becomes every role he takes, his commitment to the part is unparalleled. He shines in movies such as In the Name of the Father, There will be Blood and Gangs of New York.

As for an actress, I'm a big fan of Anne Hathaway. I think she's taken on a number of different roles, isn't type cast and isn't afraid to mix it up a little. I think she's happy to do whatever it takes, as long as it's appropriate to the role at the time.

I really like Denzel Washington. That started in the movie The Bone Collector.

Seen that movie a few times now, but still like his acting skills in that movie.
 

This is difficult to answer there are so many good actors, I really like Marcky mark whalberg in alot of films, I like the old Adam Sandler and the new Ryan Reynolds.

If you're talking action then Liam neeson is great.

I t really depends on the movie different actors have different qualities

Have to be Paul Newman, he is COOL. plain and simple. His character in HUD is an ass and yet you still think "damn that guy is cool". I also just discovered that he voiced doc hudson from CARS that is pretty cool too.

My favorite actor is Morgan Freeman. He usually plays difficult roles. In my opinion, his best film was Million Dollar Baby. Another great actor is Ben Affleck. Last week, I watched his movie The Accountant (I wish an accountant's life was that exiting).

As for actresses, I like Julia Roberts and Sandra Bullock.

So many great names listed above and Im in agreement with Nick Cage and Brad Pitt, oh and Ryan Reynolds definitely, as well Julia Roberts and Sandra Bullock. I love that they can play funny as well as serious roles. A secret favourite of mine is The Proposal. Sexy and funny.

I think my favorite actor is Jake Gyllenhaal, I mean he’s who popped up in my head immediately when I read this title. He’s a really great actor and not so rough on the eyes. For actress I think I’ll have to go with Elizabeth Moss. Love her.