Forsberg
Seasons/Games: 13 / 708
Hart: 1
AS Center: 1, 1, 1, 3, 5
Scoring: 2, 4, 5
Goals: no top-5
Assists: 1, 2, 3, 4
Selke: 2, 4
Cups: 2
Smythe: none
International: Iconic in Sweden for his WJC and 1994 Olympic performances, but his record in best-on-best tournaments isn't remarkable.
Malkin
Seasons/Games: 16 / 981
Hart: 1, 2, 2
AS Center: 1, 1, 1, 4
Scoring: 1, 1, 2, 4
Goals: 2, 4, 4, 5
Assists: 1, 3
Selke: no top-5
Cups: 3
Smythe: 1
International: Has generally played well individually, even though Team Russia has fallen short of expectations.
McDavid
Seasons/Games: 7 / 487
Hart: 1, 1, 2, 3, 5, 5
AS Center: 1, 1, 1, 1, 2, 3
Points: 1, 1, 1, 1, 2, 2
Goals: 2, 6, 6, 7, 10
Assists: 1, 1, 2, 2, 2, 3
Selke: no top-5
Cups: none
Smythe: none
International: Has never had the opportunity to play in an Olympics. Has performed well in successful lower-level international tourneys.
It's pretty clear that McDavid belongs above these guys, IMO.
I'll grant you that Malkin is showing more staying power than Forsberg, in the sense that he's out there performing at a respectable level rather than watching the game on his sofa. Some people here don't give much credit in all-time arguments to the ones who stick around and continue to contribute at a sub-superstar level... I tend to be one who assigns a little more credit for that trait, especially if it's done in the context of contributing to team success (or making a very respectable attempt).