To inject a little sales-age in here:
I forgot how this works. I know you have to agree to something to allow Nintendo to use your logged hours for research and whatnot, but I don't know where it pops up. Anyway, some Nintendo channel download/usage numbers:
Mii Channel: 2,415,819
Wii Shop: 2,241,849
Forecast Channel: 2,101,250
Nintendo Channel: 1,543,140
Check Mii Out Channel: 1,436,249
Everybody Votes Channel: 1,300,092
Internet Channel: 992,144
So with so many channels having a higher number than the Nintendo Channel, I think it's possible that Nintendo actually collects data regardless of your say-so in the Nintendo Channel. Here are the numbers I found:
Mario Series:
Mario Bros.: 44,837
Super Mario Bros.: 341,598
Super Mario Bros. Lost Levels: 71,362
Super Mario Bros. 2: 124,742
Super Mario Bros. 3: 380,858
Super Mario World: 226,108
Super Mario 64: 194,324
Zelda Series:
Zelda II: 43,528
A Link to the Past: 112,060
Ocarina of Time: 146,395
Sonic Series:
Sonic the Hedgehog: 74,634
Sonic the Hedgehog 2: 43,737
Sonic the Hedgehog 3: 39,236
Donkey Kong Series:
Donkey Kong: 83,009
Donkey Kong Country: 106,966
Donkey Kong Country 2: 45,712
Donkey Kong Country 3: 24,356
WiiWare:
1. Defend Your Castle: 79,799
2. My Pokemon Ranch: 78,704
3. Dr. Mario Rx: 63,189
4. My Life as a King: 57,238
5. My Aquarium: 55,667
6. World of Goo: 51,774
7. LostWinds: 45,172
8. Mega Man IX: 39,449
9. Tetris Party: 38,279
10. Strong Bad Episode 1: 23,190 (Strong Bad Episode 2: 7,710)
VC:
1. Super Mario Bros. 3: 380,858
2. Super Mario Bros.: 341,598
3. Super Mario World: 226,108
4. Mario Kart 64: 204,841
5. Super Mario 64: 194,324
6. Ocarina of Time: 146,395
7. Super Mario Bros. 2: 124,742
8. Punch-Out: 123,129
9. Paper Mario: 117,158
10. A Link to the Past: 112,060
N64:
1. Mario Kart 64: 204,841
2. Super Mario 64: 194,324
3. Ocarina of Time: 146,395
4. Paper Mario: 117,158
5. Star Fox 64: 104,414
6. Pokemon Snap: 64,437
7. Kirby 64: The Crystal Shards: 54,450
8. Yoshi Story: 46,705
9. Sin & Punishment: 36,838
10. F-Zero X: 22,721
NES:
1. Super Mario Bros. 3: 380,858
2. Super Mario Bros.: 341,598
3. Super Mario Bros. 2: 124,742
4. Punch-Out: 123,129
5. Kirby's Adventure: 111,789
6. Donkey Kong: 83,009
7. Pac-Man: 72,845
8. Super Mario Bros. Lost Levels: 71,362
9. Kid Icarus: 55,736
10. Excitebike: 50,789
SNES:
1. Super Mario World: 226,108
2. A Link to the Past: 112,060
3. Donkey Kong Country: 106,966
4. Super Metroid: 81,997
5. Super Mario RPG: 52,921
6. Donkey Kong Country 2: 45,712
7. Super Castlevania IV: 39,047
8. Contra III: 35,402
9. Street Fighter II World Warrior: 33,939
10. Street Fighter II Turbo: 29,359
Other stuff:
Metroid: 50,704
Galaga: 43,347
Teenage Mutant Ninja Turtles: 41,890
Tecmo Bowl: 40,555
Ninja Gaiden: 34,591
Castlevania: 33,480
Super C: 21,850
Super Street Fighter II: 22,078
Super Ghouls N Ghosts: 14,340
Gunstar Heroes: 44,552
Toejam & Earl: 28,827
Pokemon Puzzle League: 8,805
WiiWare/VC Top 10 in terms of revenue:
1. Mario Kart 64: $2,048,410
2. Super Mario 64: $1,943,240
3. Super Mario Bros. 3: $1,904,290
4. Super Mario World: $1,808,864
5. Super Mario Bros.: $1,707,990
6. Ocarina of Time: $1,463,950
7. Paper Mario: $1,171,580
8. Star Fox 64: $1,044,140
9. A Link to the Past: $896,480
10. Final Fantasy Crystal Chronicles: My Life as a King: $858,570