Driven by boredom, I've done some work with adjusted plus/minus.
There are a two major problems with the plus/minus statistic. First, it's team dependent. Second, it's era-dependent. I want to adjust for this.
To adjust for a player's team, I compare the player's PM to their team's PM (ie even strength and shorthanded goals for minus even strength and shorthanded goals against). Then I divide it by 5 to show that at any given time, 5 players are on the ice. (I just realized I should probably divide it by less than 5, maybe 4.8 or 4.9, because only 3 or 4 players are on the ice when shorthanded. Oops.)
Then we subtract the team's PM from the portion of games a player plays in. Example: in 1972 Bobby Orr was +86 and the Bruins were +142. 142/5 = +28.4. Orr played in 76/78 games (97.4%), so we subtract 97.4% of the team's PM rating from his personal PM. +86 - (28.4*.974) =58.3. [We only remove the % of games a player is in the lineup for since we don't want them to be rewarded/penalized for their team playing poorly/well when they're not playing.] Ideally I would like to break this down by ice time but I don't have enough data.
Also it's easier to accumulate high or low PM stats in high-scoring years. I adjust PM stats based on how high scoring the year is to a base of 6.5 (average goals per game since '68). So there were 6.13 goals per game in 1972, I multiply Orr's adjusted +58.3 by 6.5/6.13 = 1.06 to get +61.8. This is Orr's final adjusted PM stat.
Career leaders (not counting '04):
Bobby Orr 596 445.9
Larry Robinson 1,384 377.2
Ray Bourque 1,612 318.9
Bobby Clarke 1,144 307.8
Wayne Gretzky 1,487 282.9
Mark Howe 929 270.0
Borje Salming 1,148 241.7
Denis Potvin 1,060 237.7
Scott Stevens 1,597 236.8
Brad McCrimmon 1,222 223.9
Bryan Trottier 1,279 212.8
Al MacInnis 1,413 204.8
Eric Lindros 639 199.4
Brad Park 1,113 197.2
Dave Taylor 1,111 195.3
Guy Lafleur 1,126 191.3
Mike Bossy 752 191.0
Serge Savard 1,038 188.7
Craig Ramsay 1,070 176.7
Brian Propp 1,016 169.0
Bill Hajt 854 164.0
Jaromir Jagr 950 160.7
Joe Reekie 902 158.8
Dallas Smith 773 158.0
Jacques Laperriere 435 153.6
Andre Dupont 800 152.8
Terry Harper 795 143.0
Steve Larmer 1,006 141.6
Jimmy Watson 613 140.3
Chris Chelios 1,326 137.6
John LeClair 798 135.1
Peter Forsberg 541 134.8
Jim Schoenfeld 719 131.3
Rod Seiling 844 129.5
Petr Svoboda 1,046 128.3
Mario Lemieux 879 128.2
Jere Lehtinen 510 127.9
Steve Shutt 930 125.4
Charlie Simmer 712 124.6
Jean Ratelle 1,022 123.7
Keith Carney 729 121.7
Mike Modano 1,025 121.4
Sergei Fedorov 908 119.3
Don Luce 894 118.4
Jeremy Roenick 1,062 118.0
Rod Langway 994 116.5
Chris Pronger 642 116.5
Gary Roberts 957 116.2
Steve Sullivan 517 115.4
Bill Barber 903 114.5
Top 50 Single Seasons (not counting '04):
Bobby Orr 1971 Boston Bruins : 84.7
Larry Robinson 1977 Montreal Canadiens : 76.3
Bobby Orr 1972 Boston Bruins : 61.8
Wayne Gretzky 1985 Edmonton Oilers : 61.3
Bobby Orr 1974 Boston Bruins : 58.7
Dallas Smith 1971 Boston Bruins : 56.3
Bobby Orr 1975 Boston Bruins : 56.1
Jacques Laperriere 1973 Montreal Canadiens : 55.6
Rick Smith 1972 California Golden Seals : 53.6
Mark Howe 1986 Philadelphia Flyers : 53.5
Bobby Orr 1969 Boston Bruins : 53.3
Bobby Clarke 1976 Philadelphia Flyers : 52
Bobby Clarke 1975 Philadelphia Flyers : 52
Brad McCrimmon 1986 Philadelphia Flyers : 51.2
Peter Forsberg 2003 Colorado Avalanche : 51.1
Milan Hejduk 2003 Colorado Avalanche : 49.9
Charlie Simmer 1980 Los Angeles Kings : 47.1
Rick Smith 1978 Boston Bruins : 45.6
Frank Mahovlich 1969 Detroit Red Wings : 45.5
Wayne Gretzky 1982 Edmonton Oilers : 45.1
Jari Kurri 1985 Edmonton Oilers : 44.7
Bobby Orr 1970 Boston Bruins : 44.7
Bryan Trottier 1979 New York Islanders : 44.6
Peter Popovic 1996 Montreal Canadiens : 44.5
Gary Bergman 1969 Detroit Red Wings : 44.4
Gordie Howe 1969 Detroit Red Wings : 44.4
Guy Lafleur 1977 Montreal Canadiens : 44.4
Bryan Trottier 1984 New York Islanders : 44
Steve Shutt 1977 Montreal Canadiens : 43.4
Brad Park 1978 Boston Bruins : 43.3
Chris Pronger 1998 St. Louis Blues : 43.3
Wayne Gretzky 1987 Edmonton Oilers : 43.1
Jean Ratelle 1972 New York Rangers : 42.5
Alex Delvecchio 1969 Detroit Red Wings : 42.5
Bill Barber 1976 Philadelphia Flyers : 42.1
Phil Esposito 1969 Boston Bruins : 41.7
Alexander Karpovtsev 1999 Toronto Maple Leafs : 41.5
Ian Turnbull 1977 Toronto Maple Leafs : 41.4
Brian Engblom 1982 Montreal Canadiens : 41.4
Serge Savard 1973 Montreal Canadiens : 41.2
Reggie Leach 1976 Philadelphia Flyers : 41.1
Denis Potvin 1979 New York Islanders : 41
Mike Bossy 1984 New York Islanders : 40.9
Murray Baron 1996 St. Louis Blues : 40.5
Chris Pronger 2000 St. Louis Blues : 40.3
Borje Salming 1977 Toronto Maple Leafs : 39.7
Dave Taylor 1980 Los Angeles Kings : 39.6
Serge Savard 1975 Montreal Canadiens : 39.4
Brad Park 1972 New York Rangers : 39.4
Wayne Gretzky 1984 Edmonton Oilers : 38.8
The lists actually aren't very different from the unadjusted list, but it lets us see that stars that played on stacked teams in high-scoring eras aren't quite as impressive as unadjusted stats show us. (Except for Orr. He should get a national holiday).