Bruno's list looks like nice compromise between my version and Luuk's. I am willing to go with it until further notice.

1. Buster Keaton
2. Jack Lemmon
3. Harold Lloyd
4. Burt Lancaster
5. Klaus Kinski
6. Peter Lorre
7. Max Linder
8. Gene Kelly
9. Charles Laughton
10. Groucho Marx / The Marx Brothers
11. Ben Kingsley
12. Laurel and Hardy
13. Jean-Pierre Léaud
14. Fredric March
15. James Mason
16. Tony Chiu Wai Leung
17. Jean Marais
18. Jerry Lewis
19. Boris Karloff
20. Dilip Kumar
21. Bruce Lee
22. Aamir Khan
23. Lee Marvin
24. Nino Manfredi
25. Christopher Lee
26. Karl Malden
27. Bela Lugosi
28. John Malkovich
29. Heath Ledger
30. Harvey Keitel
31. Rudolf Klein-Rogge
32. Takeshi Kitano
33. Martin Landau
34. Steve Martin
35. Fred MacMurray
36. Jet Li
37. Kevin Kline

Although Lancaster is more acclaimed and popular, Lloyd beats him in influence and cultural impact by a bigger margin.

Lloyd was also very popular during silent era himself.

I'd say it breaks down like this:

Influence: Lloyd
Acclaim: Lancaster
Popular and cultural recognition: close but Lloyd
Body of work: Lancaster

Overall, I'd prefer to keep Lancaster ahead.

I think there is an important distinction that needs to be made, not just here but for the future as well. The film Batman Begins is acclaimed, and the acting overall was generally acclaimed, but never did anybody make a single remark about Rutger Hauer's performance. Ditto for Sin City. I've seen it a lot on here where an actor was given credit for appearing in an acclaimed film as if that acclaim is their own individually. Christopher Lee was in '48 Hamlet, it has absolutely nothing to do with his legacy or ability that he was in one of the most lauded films of the time.

If you are combining popularity and cultural impact, then Lloyd beats Lancaster by an important enough margin. As you said earlier, they are both popular, then add on the enormous cultural impact of the character created by Lloyd as well as that of the famous "clock scene" and Lloyd comes out as a clear winner.

I agree with Sherick that body of work for sake of this list shouldn't be treated like it was for sake of directors list. Actors are generally much less responsible for film's quality than directors are, especially when it comes to cameo-like performances like in Hauer's case.

1. Buster Keaton
2. Jack Lemmon
3. Harold Lloyd/Burt Lancaster
4. Burt Lancaster/Harold Lloyd
5. Klaus Kinski
6. Gene Kelly
7. Peter Lorre
8. Charles Laughton
9. Max Linder
10. Groucho Marx / The Marx Brothers
11. Ben Kingsley
12. Fredric March
13. Laurel and Hardy
14. Jean-Pierre Léaud
15. James Mason
16. Tony Chiu Wai Leung
17. Boris Karloff
18. Dilip Kumar
19. Jean Marais
20. Jerry Lewis
21. Lee Marvin
22. Nino Manfredi
23. Bruce Lee
24. Aamir Khan
25. Christopher Lee
26. Karl Malden
27. Heath Ledger
28. Bela Lugosi
29. Harvey Keitel
30. John Malkovich
31. Rudolf Klein-Rogge
32. Takeshi Kitano
33. Steve Martin
34. Martin Landau
35. Fred MacMurray
36. Kevin Kline
37. Jet Li

Something like this for compromise.

I think I'd prefer to have Lancaster above Lloyd. Lancaster can be credited with significant influence and cultural impact himself, being among more independently minded actors of his era and cited as inspiration by Robert Redford.

Agreed.

1. Laurence Olivier
2. Paul Newman
3. Jack Nicholson
4. Toshiro Mifune
5. Marcello Mastroianni
6. Al Pacino
7. Gregory Peck
8. Peter O'Toole
9. Robert Mitchum
10. Michel Piccoli
11. Sean Penn
12. Tatsuya Nakadai
13. Phillipe Noiret
14. Bill Murray
15. Gary Oldman
16. Walter Matthau
17. Yves Montand
18. Steve McQueen
19. Liam Neeson
20. Ian McKellen
21. Paul Muni
22. David Niven
23. Edward Norton
24. Thomas Mitchell
25. Nanni Moretti
26. Joe Pesci
27. Joaquin Phoenix
28. Joel McCrea
29. Viggo Mortensen
30. Victor McLaglen
31. Armin Mueller-Stahl
32. Franco Nero
33. Matthew McConaughey
34. Nick Nolte
35. Robert Montgomery
36. Ulrich Mühe
37. Masahiro Motoki

You can make an argument for completely different ordering of top six but mine feels rather uncontroversial (Pacino at #6 aside)

1. Laurence Olivier
2. Paul Newman
3. Jack Nicholson
4. Toshiro Mifune
5. Al Pacino
6. Marcello Mastroianni
7. Gregory Peck
8. Peter O'Toole
9. Robert Mitchum
10. Michel Piccoli
11. Sean Penn
12. Tatsuya Nakadai
13. Philippe Noiret
14. Bill Murray
15. Gary Oldman
16. Walter Matthau
17. Yves Montand
18. Steve McQueen
19. Ian McKellen
20. Paul Muni
21. Liam Neeson
22. David Niven
23. Edward Norton
24. Thomas Mitchell
25. Nanni Moretti
26. Joel McCrea
27. Viggo Mortensen
28. Victor McLaglen
29. Armin Mueller-Stahl
30. Joe Pesci
31. Joaquin Phoenix
32. Franco Nero
33. Matthew McConaughey
34. Robert Montgomery
35. Ulrich Mühe
36. Nick Nolte
37. Masahiro Motoki

Still not entirely comfortable with Newman over Nicholson, though... As somebody pointed out earlier, Newman's cultural impact because of his philantrophy and autoracing obsession doesn't relate too much with his acting. By the way, I could also see Mifune at #2, but let's see how the others think about that.

1. Laurence Olivier
2. Paul Newman
3. Jack Nicholson
4. Al Pacino
5. Toshiro Mifune
6. Marcello Mastroianni
7. Gregory Peck
8. Peter O'Toole
9. Robert Mitchum
10. Michel Piccoli
11. Sean Penn
12. Tatsuya Nakadai
13. Philippe Noiret
14. Bill Murray
15. Gary Oldman
16. Walter Matthau
17. Yves Montand
18. Steve McQueen
19. Ian McKellen
20. Liam Neeson
21. Paul Muni
22. David Niven
23. Edward Norton
24. Joe Pesci
25. Thomas Mitchell
26. Nanni Moretti
27. Joaquin Phoenix
28. Joel McCrea
29. Viggo Mortensen
30. Victor McLaglen
31. Armin Mueller-Stahl
32. Matthew McConaughey
33. Franco Nero
34. Nick Nolte
35. Robert Montgomery
36. Ulrich Mühe
37. Masahiro Motoki


And I put Pacino in this battle too, very hard to define this top 4.

I think Mifune and Mastroianni are giant actors, but they are on a step down, in my opinion, especially in acclaim and popularity.

I'd say even if we ignore Newman's philanthropy and autoracing contributions (and I'm ok with that) he still comfortably beats Jack in both influence and popularity while the rest of criteria are close. Also don't agree with Mifune and Mastroianni being step behind Pacino. They are clearly two most famous and respected non-english language actors, at least in the West. Mastroianni for example has three Academy nominations which is unique feat for "foreign" actor. On the other hand, Pacino generally strikes me as least popular out of "big four".

1. Laurence Olivier
2. Paul Newman
3. Toshiro Mifune
4. Marcello Mastroianni
5. Jack Nicholson
6. Al Pacino
7. Gregory Peck
8. Peter O'Toole
9. Robert Mitchum
10. Michel Piccoli
11. Sean Penn
12. Tatsuya Nakadai
13. Philippe Noiret
14. Bill Murray
15. Gary Oldman
16. Walter Matthau
17. Yves Montand
18. Steve McQueen
19. Ian McKellen
20. Paul Muni
21. Liam Neeson
22. Thomas Mitchell
23. Nanni Moretti
24. Joel McCrea
25. Viggo Mortensen
26. Victor McLaglen
27. David Niven
28. Edward Norton
29. Armin Mueller-Stahl
30. Joe Pesci
31. Matthew McConaughey
32. Joaquin Phoenix
33. Robert Montgomery
34. Ulrich Mühe
35. Masahiro Motoki
36. Franco Nero
37. Nick Nolte

The top 6 is very, very close.