DS, the system with the best ever lineup of games IMO, limiting it to just 10 is hard.
10. Metroid Prime: Hunters
9. Dragon Quest IX
8. Pokemon Diamond/Pearl
7. Final Fantasy Tactics A2
6. Advance Wars: Dark Conflict
5. Final Fantasy IV DS
4. Chrono Trigger DS
3. The World Ends With You
2. Pokemon Black/White
1. Mario Kart DS