For posterity's sake, these are the numbers that were current as of the 11th of June in 2010:
1. Wii Sports - 63.08 million sold
2. Wii Play - 27.41 million sold
3. Nintendogs - 23.71 million sold
4. Wii Fit - 22.56 million sold
5. Mario Kart Wii - 22.32 million sales
6. New Super Mario Bros. - 22.02 million sold
7. Brain Age: Train Your Brain in Minutes a Day - 19.13 million sold
8. Call of Duty: Modern Warfare 2 - 18.94 million sold (10.94 million 360, 8.00 million PS3)
9. Mario Kart DS - 18.09
10. Pokemon Diamond/Pearl - 17.49
11. Wii Sports Resort - 15.84 million sold
12. Brain Age 2 - 14.80 million sold
13. New Super Mario Bros. Wii - 14.76 million sold
14. Grand Theft Auto IV - 14.39 million sold (7.83 Xbox 360, 6.56 PS3)
15. Call of Duty 4: Modern Warfare - 14.36 million sold (8.3 million Xbox 360, 5.25 million PS3, 0.81 million DS)
16. Wii Fit Plus - 12.62 million sold
17. Call of Duty: World at War - 12.54 million sold (6.37 Xbox 360, 4.04 PS3, 1.49 Wii, 0.64 DS)
18. Mario and Sonic at the Olympic Games - 12.39 million sold (7.60 Wii, 4.79 DS)
19. Animal Crossing: Wild World - 11.24 million sold
20. Halo 3 - 11.01 million sold
21. Guitar Hero III: Legends of Rock - 10.78 million sold (4.40 million Wii, 4.39 million 360, 1.99 million PS3)
22. LEGO Star Wars: The Complete Saga - 9.82 million sold (3.53 million Wii, 3.47 million DS, 1.59 million 360, 1.23 million PS3)
23. Super Smash Bros. Brawl - 9.48 million sold
24. Super Mario Galaxy - 8.67 million sold
25. Assassin's Creed - 8.61 million sold (4.86 million 360, 3.75 million PS3)
26. Super Mario 64 DS - 8.37 million sold
27. LEGO Indiana Jones: The Original Adventures - 7.84 million sold (3.54 million 360, 1.74 million DS, 1.73 million Wii, 0.83 million PSP, 0.68 million PS3)
28. Pokemon Heart Gold/Soul Silver - 7.81
29. FIFA Soccer 10 - 7.75 million sold (3.31 million PS3, 2.54 million 360, 0.79 million Wii, 0.69 million PSP, 0.42 million DS)
30. Guitar Hero: World Tour - 7.44 million sold (3.42 million Wii, 2.48 million 360, 1.54 PS3)
31. Assassin's Creed II - 7.39 million sold (3.83 million 360, 3.56 million PS3)
32. Mario Party 8 - 7.07 million sold
33. LEGO Batman: The Videogame - 7.00 million sold (2.57 million 360, 1.61 million Wii, 1.53 million DS, 0.77 million PSP, 0.52 million PS3)
34. Pokemon Platinum - 6.96 million sold
35. Star Wars: The Force Unleashed - 6.79 million sold (2.23 million 360, 1.58 million PS3, 1.47 million Wii, 0.78 million PSP, 0.73 million DS)
36. Mario Party DS - 6.60 million sold
37. Big Brain Academy - 6.47 million sold
38. FIFA Soccer 08 - 6.15 million sold (1.69 million PS3, 1.46 million 360, 1.15 million PSP, 1.00 million Wii, 0.85 million DS)
39. Grand Theft Auto: Liberty City Stories - 6.10 million sold
40. Gears of War - 6.06 million sold
41. Mario & Sonic at the Olympic Winter Games - 6.00 million sold (3.31 million Wii, 2.69 million DS)
42. Resident Evil 5 - 5.98 million sold (3.23 million PS3, 2.75 million 360)
43. FIFA Soccer 09 - 5.96 million sold (2.43 million PS3, 2.06 million 360, 1.04 million PSP, 0.43 mllion DS)
44. Gears of War 2 - 5.73 million sold
45. Madden NFL 10 - 5.63 million sold (2.46 million 360, 1.94 million PS3, 0.68 million Wii, 0.55 million PSP)
46. The Legend of Zelda: Twilight Princess - 5.56 million sold
47. Need for Speed: ProStreet - 5.51 million sold (2.08 million 360, 1.79 million PS3, 0.93 million Wii, 0.60 million PSP, 0.11 million DS)
48. Kung Fu Panda - 5.48 million sold (3.08 million 360, 1.16 million DS, 0.82 million Wii, 0.42 million PS3)
49. Final Fantasy XIII - 5.43 million sold (4.05 million PS3, 1.38 million 360)
50. Fallout 3 - 5.27 million sold (3.12 million 350, 2.15 million PS3)
yes, I am updating the list right now. It will take several hours - compiling numbers and making new writeups takes time. I will post again when it's finished.
