Fire Emblem is very different to Mario/Zelda. And is also a lot of fun.

Pokémon is Pokémon, it's exactly what you'd expect

New Super Mario 2 is good fun, but you've already a Mario game

Same for OoT

Not played any of the others, although they're mostly platformers, so if you fancy that, go for it.

One of my colleagues got Luigis Mansion 2 for her 7 year old daughter who absolutely loves it. Make of that what you will.

Looks like Fire Emblem is winning by a good margin,

I didnt realise Paper Mario was soo bad :(

I take it there is no real difference between X and Y, as in ones not better than the other.

I remember loving Luigis mansion at launch on Gamecube, but i dont see people talk about the new one much.

Btw they have demos for Dream Team, Bravely Default, and Awakening, aswell as plenty of other games like Phoenix Wright and Resident Evil, so be sure to try those out!

It's easier to eliminate some games off that list. Paper Mario and Mario Party can come off that list. You can't go wrong after that. I would honestly recommend Ocarina of Time 3D. I'd also recommend Mario & Luigi Dream Team... I hated the start of the game, but it's really enjoyable once you get going. It has a tons of gameplay hours too, so it'll keep you busy for a while. Fire Emblem also offers you good game time.

Ocarina of Time 3D
Mario & Luigi Dream Team
Mario Kart 7
Fire Emblem

Paper Mario is still worth checking out if you can find it for cheap.

Yes it is the worst of them all, yes worse than Super Paper Mario.

It still has it´s redeeming qualitys (great soundtrack and visuals, good gameplay- albeit different, good length).

If you want a more traditional paper mario game, go for Dream Team Brothers.

I think you should buy Castelvania Miror of Fate. Its cheap and its pretty good if youre not a fan of the classic games

Fire Emblem and Pokemon are musts, but seriously consider Phoenix Wright: Duel Destinies - it's eShop only, so they've made it cheaper than other games (despite having as much if not more content than other games in the series)

Fire Emblem Awakening or Bravely Default.

Kid Icarus: Uprising

I don't know, I don't have much 3DS games.