I went and made a rankings list based on tournament performance. I'm also continually updating it. Basically, +1 for placing top8, +3 for placing top4, +5 for winning a tournament. And if you want your tournament to count, give me a top8 listing with character mains. ^_^
S Rank will see THE MOST representation in a tournament, by far. Especially toward the top. The A Rank characters tend to see varying representation in different regions of the country, but wherever they're big, they'll usually take a top4 or even winning spot. B Rank is interesting... it mostly shows characters that have been doing relatively well in tourneys, though likely only showing up in local ones and thus not seeing as much play as S and A Ranks have. C Rank is popular characters that haven't really placed well, D Rank is just plain unpopular.
S Rank
Meta Knight (19 top8, 19 top4, 5 wins, 101 pts)
Snake (13 top8, 14 top4, 9 wins, 100 pts)
A Rank
King Dedede (3 top8, 10 top4, 4 wins, 53 pts)
Mr. Game & Watch (11 top8, 6 top4, 4 wins, 49 pts)
ROB (9 top8, 10 top4, 1 win, 44 pts)
Wario (1 top8, 4 top4, 6 wins, 43 pts)
Marth (10 top8, 6 top4, 2 wins, 38 pts)
Pikachu (3 top8, 8 top4, 2 wins, 37 pts)
B Rank
Wolf (7 top8, 7 top4, 28 pts)
Ike (7 top8, 5 top4, 1 win, 27 pts)
Kirby (7 top4, 1 win, 26 pts)
Lucario (3 top8, 4 top4, 2 wins, 25 pts)
Toon Link (3 top8, 4 top4, 2 wins, 25 pts)
Peach (2 top8, 6 top4, 1 win, 25 pts)
Fox (5 top8, 5 top4, 1 win, 25 pts)
Olimar (9 top8, 5 top4, 24 pts)
Falco (5 top8, 4 top4, 1 win, 22 pts)
Sonic (3 top8, 2 top4, 2 wins, 19 pts)
Donkey Kong (5 top8, 1 top4, 2 win, 18 pts)
C Rank
Pit (4 top8, 2 top4, 1 win, 15 pts)
Ice Climbers (3 top8, 4 top4, 15 pts)
Diddy Kong (4 top8, 3 top4, 13 pts)
Lucas (4 top8, 3 top4, 13 pts)
Bowser (1 top8, 3 top4, 10 pts)
Jigglypuff (3 top8, 2 top4, 9 pts)
Luigi (2 top4, 6 pts)
Captain Falcon (2 top4, 6 pts)
Zero Suit Samus (3 top8, 1 top4, 6 pts)
Mario (2 top8, 1 top4, 5 pts)
Ness (2 top8, 1 top4, 5 pts)
D Rank
Link (1 top8, 1 top4, 4 pts)
Sheik (1 top8, 1 top4, 4 pts)
Zelda (1 top4, 3 pts)
Yoshi (1 top4, 3 pts)
Pokémon Trainer (1 top4, 3 pts)
Ganondorf (3 top8, 3 pts)
Samus (2 top8, 2 pts)
Tournament Wins ONLY List
Snake (9 wins)
Wario (6 wins)
Meta Knight (5 wins)
Mr. Game & Watch (4 wins)
King Dedede (4 wins)
Pikachu (2 wins)
Marth (2 wins)
Toon Link (2 wins)
Lucario (2 wins)
Sonic (2 wins)
Donkey Kong (2 wins)
ROB (1 win)
Kirby (1 win)
Ike (1 win)
Peach (1 win)
Fox (1 win)
Falco (1 win)
Pit (1 win)
No Top8 List
S Rank
Snake (14 top4, 9 wins, 87 pts)
Meta Knight (19 top4, 5 wins, 82 pts)
A Rank
King Dedede (10 top4, 4 wins, 50 pts)
Wario (4 top4, 6 wins, 42 pts)
Mr. Game & Watch (6 top4, 4 wins, 38 pts)
ROB (10 top4, 1 win, 35 pts)
Pikachu (8 top4, 2 wins, 34 pts)
Marth (6 top4, 2 wins, 28 pts)
Kirby (7 top4, 1 win, 26 pts)
B Rank
Peach (6 top4, 1 win, 23 pts)
Lucario (4 top4, 2 wins, 22 pts)
Toon Link (4 top4, 2 wins, 22 pts)
Wolf (7 top4, 21 pts)
Fox (5 top4, 1 win, 20 pts)
Ike (5 top4, 1 win, 20 pts)
Falco (4 top4, 1 win, 17 pts)
Sonic (2 top4, 2 wins, 16 pts)
Olimar (5 top4, 15 pts)
Donkey Kong (1 top4, 2 wins, 13 pts)
C Rank
Ice Climbers (4 top4, 12 pts)
Pit (2 top4, 1 win, 11 pts)
Bowser (3 top4, 9 pts)
Diddy Kong (3 top4, 9 pts)
Lucas (3 top4, 9 pts)
Luigi (2 top4, 6 pts)
Captain Falcon (2 top4, 6 pts)
D Rank
Yoshi (1 top4, 3 pts)
Sheik (1 top4, 3 pts)
Link (1 top4, 3 pts)
Zelda (1 top4, 3 pts)
Mario (1 top4, 3 pts)
Zero Suit Samus (1 top4, 3 pts)
Pokémon Trainer (1 top4, 3 pts)
Jigglypuff (1 top4, 3 pts)
Ness (1 top4, 3 pts)
Unranked
Ganondorf
Samus
Tournaments Used (thanks to Xiivi for links!)
XESTICLE
http://smashboards.com/showthread.php?t=164253
C3
http://smashboards.com/showthread.php?t=164150
Final Smash 3
http://smashboards.com/showthread.php?t=164129
UofM Biweekly 11
http://smashboards.com/showthread.php?t=110735
UofM Biweekly 12
http://smashboards.com/showthread.php?t=110735
UofM Biweekly 13
http://smashboards.com/showthread.php?t=110735
UofM Biweekly 14
http://smashboards.com/showthread.php?t=110735
Indiana Brawl Tournament
http://smashboards.com/showthread.php?t=164106
Arena 51 Biweekly
http://smashboards.com/showthread.php?t=164316
Lolful
http://smashboards.com/showthread.php?t=162695
Trash Day 4
http://smashboards.com/showthread.php?t=162864
Capital Brawl
http://smashboards.com/showthread.php?t=161093
Dallas Blockbuster Brawl
http://smashboards.com/showthread.php?t=165642
The Drunken Brawl
http://smashboards.com/showthread.php?t=165463
Michigan Biweekly 1 @ DigiOps
http://smashboards.com/showthread.php?t=161768
Your Brawl @ Rochester, NY
http://smashboards.com/showthread.php?t=165399
Bel Gusto
http://smashboards.com/showthread.php?t=165643
This Game Sucks
http://smashboards.com/showthread.php?t=157451
Smashtastrophe 2
http://smashboards.com/showthread.php?t=165793
Darkside Comics
http://smashboards.com/showthread.php?t=165535
DUMB
http://smashboards.com/showthread.php?t=159937
Final Round XI
http://smashboards.com/showthread.php?t=154544
MPS
PLAY N TRADE
http://smashboards.com/showthread.php?t=161576
Critical Hit
http://smashboards.com/showthread.php?t=161926
Omaha NE Family Fun Center
http://smashboards.com/showthread.php?t=165900
Get Some
http://smashboards.com/showthread.php?t=139009
EWU II
FB3: The Shocker
http://smashboards.com/showthread.php?t=127388
NikoK's Niagara Triweeklies
http://smashboards.com/showthread.php?t=148705
Panama Weeklies
Rochester's First Brawl
http://smashboards.com/showthread.php?t=156664
Albuquerque Monthly
http://smashboards.com/showthread.php?t=104253
New York Weekly
http://smashboards.com/showthread.php?t=96076
ROFL's Palmdale: Tauntsies Two
http://smashboards.com/showthread.php?t=162950