Meant to post in this thread many months ago ...
Eep... me too! It's a good thread idea, but I wasn't using my 3DS very much when it got posted and then I just kind of forgot to come back later.

My items below, although with the following caveats:
a) I tried to remove non-game stuff like SwapNote, Netflix, etc
b) some of the times aren't exactly accurate (usually either because of sharing with my kids, or falling asleep while the game was turned on)
c) I own a couple of older DS consoles, and actually play a lot of DS games on them instead of the 3DS... so it wouldn't surprise me if there are a couple DS games that could've fit here but just weren't played on this system...
By Playtime1. Animal Crossing: New Leaf - 493:20
2. Pokemon Shuffle - 276:56
3. Nintendo Badge Arcade - 173:04
4. Pokemon Rumble World - 170:57
5. AlphaBounce - 119:45
6. Zen Pinball 3D - 89:56
7. Resident Evil: Revelations - 87:41
8. Petit Computer - 86:31
9. Etrian Odyssey IV - 83:22
10. Etrian Odyssey Untold - 79:33
11. Dragon Quest IX - 76:12
12. Ghost Recon Shadow Wars - 74:19
13. Dragon Quest VI - 61:28
14. StreetPass Mii Plaza - 58:49
15. Monster Hunter 3 Ultimate - 51:09
16. Colors! 3D - 47:01
17. Zero Escape: Virtue's Last Reward - 41:03
18. Marvel Pinball 3D - 39:44
19. Dragon Quest IV - 38:40
20. FreakyForms - 32:12
By Play Frequency1. Pokemon Shuffle - 1,062
2. Nintendo Badge Arcade - 684
3. Pokemon Rumble World - 583
4. Animal Crossing: New Leaf - 502
5. Zen Pinball 3D - 223
6. AlphaBounce - 173
7. Colors! 3D - 146
8. Resident Evil Revelations - 129
9. Petit Computer - 119
10. Dragon Question IX - 108
11. FreakyForms - 94
12. Etrian Odyssey Untold - 89
13. Etrian Odyssey IV - 79
14. PiCTOBiTS - 75
15. Marvel Pinball 3D - 74
16. Dragon Quest IV - 74
17. Dragon Quest VI - 72
18. Star Wars Pinball - 69
19. Ghost Recon Shadow Wars - 62
20. Pushmo - 55
By Average Time Played1. Dragon Quest Heroes: Rocket Slime - 1:24
2. Zero Escape: Virtue's Last Reward - 1:24
3. Clubhouse Games - 1:21
4. Severed - 1:16
5. Battles of Prince of Persia - 1:12
6. Ghost Recon Shadow Wars - 1:11
7. Tri Force Heroes - 1:09
8. Shantae: Risky's Revenge - 1:07
9. CATAN - 1:05
10. Professor Layton and the Curious Village - 1:04
11. Etrian Odyssey IV - 1:03
12. Legend of Zelda: Oracle of Seasons - 1:02
13. Monster Hunter 3 Ultimate - 1:02
14. Castlevania: Mirror of Fate - 1:01
15. Animal Crossing: New Leaf - 0:58
16. Attack of the Friday Monsters - 0:54
17. Mario and Donkey Kong - 0:54
18. Etrian Odyssey Untold - 0:53
19. Dragon Quest VI - 0:51
20. Crimson Shroud - 0:50
21. Majora's Mask - 0:50 (added one extra because it's a pretty great game and had the same average play time)
Steps Taken2,820,219 <-- this is my 3rd 3DS; do these carry over? it seems low, but since getting an XL long ago I basically never walk with the system - it's too big for my pockets!
Titles Played301
One observation after looking at that list is that it was dominated by some mediocre games that get played often for short periods of time.
I've probably asked this before, but what do you find appealing about something like the Badge Arcade? There's not much to actually do in it. Though I guess with the way you played Animal Crossing, the answer is probably simply that you have an addictive personality, hee hee.
...
I also have spent way too much time with Badge Arcade... but it kind of became a morning habit to flip in and get a few badges. Actually, I like having the option to decorate my screen sometimes too - although it's really just Animal Crossing, Mario, and Pikmin badges that I ever end up using.
The one thing I don't do with badge arcade is spend money... but as a purely free activity it's pretty ok in my books.