First of all  it is important to understand the difference between Acting and Performance ( Tamasha). Most of Bollywood actors and the audiences call Tamasha an acting. Greater the tamasha greater the acting they think it is. An actor is a person who brings life to the character in the script for the audiences. In bollywood and kollywood, first of all there is no concept of acting and second the "actors" present themsleves as opposed to the character that is in the story. Performers like Sharukh Khan and Amitabh Bachhan present Sharukh Khan and Amitabh bachhan no matter what character they play. But actors like Naseeruddhin Shah and Om Puri try to bring the character into life. Being said that here are the list of some of my favorite actors:

Hollywood Actors: Kevin Spacey, Tom Hanks, Sean Penn, Phillip Seymore Hoffman, Bill murray, Merrril Streep, Guy Pierce, Robert Dinero, Don Cheadle
Hollywood Honorable Mentions: Ed Norton, Al Pacino, Kevin Costner, Robert Duval, George Clooney, Clint Eastwood

Bollywood Actors: Nasseruddin Shah, Om Puri, Amol Palekar, Nutan, Shabana Aazmi ( i could have missed one or two on this list here but there are not many Bollywood actors who knows what acting means.

Bollywood Honorable Mentions: Irfaan Khan, Vidya Balaan, Amir Khan, Raj Babbar, Smita Patil, Kadar Khan


Kollywood Actors: ZERO, NONE, NADA

Kollywood Honorable Actors: Rajesh Hamal ( Believe it or not but if you have to rank any of the Kollywood actors then is the number one. Not that i think he is a good actor but he is the best among all we have in Kollywood.