Wow! This has really made me realise how much I play my 3DS! OK, first of all, I seperate my play time as 3DS software (with special dispension given to Pokemon Black) and the download software and DS games, so I will give seperate tables. Second of all, a lot of time on Pokemon Black was spent on a DSi, so the actual figure is more like 120 hours.
3DS Software + Pokemon Black
1-SSFIV: 3D Edition (85:51)
2- LoZ: OoT 3D (74:03)
3- Pokemon Black (73:13)
4- Mario Kart 7 (71:36)
5- Tetris (69:42)
6- Ridge Racer 3D (68:57)
7- Super Monkey Ball 3D (53:38)
8- Super Mario 3D Land (47:35)
9- Ghost Recon Shadow Wars (46:41)
10- Nintendogs + Cats (44:15)
11- Kid Icarus: Uprising (42:26)
12- Pilotwings Resort (38:16)
Other Software:
1- Freakyforms (32:31)
2-Pullblox (26:41)
3- Dillon's Rolling Western (21:21)
4- Super Mario Bros. (17:21)
5- Zen Pinball 3D (16:03)
6- LoZ: Link's Awakening (15:34)
7- Pyramids (14:56)
8- Telegraph Sudoku + Kakuro (13:15)
9- WarioWare: Mega Microgame$ (9:54)
10- Fire Emblem: TSS (9:46)
TOTAL Play Time up to this date: 2161:27
Internet App: 646:57 (which explains the ridiculous total play time - my 3DS is my main source of internet)
Note: I still Play Mario Kart, Tetris, Kid Icarus, Rolling Western, WarioWare, Fire Emblem and several other (download) games not on the list.