Awesome thread idea! My Top 10 consists of:
1. Pokémon HeartGold (165:53)
2. Theatrhythm Final Fantasy (111:44)
3. Pokémon Black Version 2 (101:40)
4. SMT IV (97:37)
5. Super Smash Bros. (90:15)
6. Theatrhythm Final Fantasy Curtain Call (83:38)
7. Fire Emblem Awakening (79:55)
8. Project X Zone (78:25)
9. Pokémon Y (77:58)
10. Pokémon Black Version (77:38)