1. NL. The changes in this game where phenomenal, the amount of town customization, the first time furniture could be customized, the first time you could customize your outfit to be more than just a dress/t-shirt (I could finally dress my female character in a cute pair of pants and a sweater for winter <3) oh and the first time you could cross-dress. Villagers do so many more things now (actually visit shops, drop by randomly, etc.) and that still doesn't cover it.
2. GC. For some reason this game has something special to it that hasn't been replicated since, I can't quite put my finger on it. I love the personalities of the villagers, all the little events where the villagers actively participate (like the sporting one), the tedious errands, the whole aesthetic of it with the gyroid by the house and idk it just makes me happy to play this game.
3. Wild World. Okay, I admit this game hasn't aged well but still it added a lot to the series. Wi-Fi, villager pictures, no faraway museum, hats and hairstyles and a lot more. Portable for the first time too, I think Animal Crossing is the best when it's portable. Oh the golden axe trading event! That's fun!
4. HHD. It's not my cup of tea but I can't deny it's really well made and it deserves to be above the next two games.
5. CF. The city was basically a cluster of characters already in the animal crossing series and it was basically a nicer looking Wild World without the dialogue. CF was the point in the series where the villager dialogue went downhill.
I appreciated Label's story though that was nice. Also nice that it brought back a lot of things from the GC version: the holidays, the ramps, the houses no longer being shared, etc. So really it's not a bad game at all, it just didn't really add much to the series.
6. AF. Enough said.