Bought mine for Animal Crossing New Leaf in summer 2013. Was never a huge fan of handheld gaming but Animal Crossing is one of my favourite series. Put over 100 hours into it since then and still visit my town on most days. Not really played many of the "big" games apart from Pokemon X, which was the first Pokemon game I've played properly and I completed it after around 30 hours. Not really interested in the post-game stuff though.
Most of my enjoyment has come from the eShop - loads of original, exciting games covering a range of genres. The Sega 3D Classics line has also been one of the console's success stories.
My most-played games
1. Animal Crossing: New Leaf - 111h
2. Professor Layton vs Phoenix Wright - 38h
3. Nintendo Pocket Football Club - 38h
4. Phoenix Wright: Dual Destinies - 35h
5. Ocarina of Time 3D - 35h (and counting
)
6. Pokemon X - 32h
7. Mighty Switch Force! - 11h
8. Fire Emblem Awakening - 9h (never really been able to get into this, will try again though)
9. Crimson Shroud - 8h
10. 3D Streets of Rage - 7h
3D has gone from a gimmick to something I miss when it's not available. Really adds something to a game when it's done well.