A placeholder to post mine when I get home later.
Edit: here's mine. I played some new games, but the playtime all fell outside of the top ten. To be fair, I didn't play my 3DS all that much in the past several months.
1. Project X Zone - 62:56
2. Bravely Default - 59:41
3. Fire Emblem Awakening - 44:58
4. Radiant Historia - 43:51
5. Dragon Quest IX - 30:34
6. Senran Kagura Burst - 23:57
7. Fire Emblem: Shadow Dragon - 21:17
8. Theatrhythm: Curtain Call - 14:45
9. Theatrhythm - 8:45
10. Street Pass/Mii Plaza - 7:55
Only difference is that I spent some more time playing DLC in Curtain Call.