They're all lovely! But, I love this one a little more than the others because it really looks like its got Spring written all over it! I also adored Rarity's Dress 1. So chic!

I'm not a fashion person, but I definitly love this dress!

I just love this style! (and the mane)

I like a lot of these! I still love AJ's gala outfit; it's not only really awesome/cool/cute, but it suits Applejack perfectly (Wayell, for dressin' up all fancy-like).
Some others of these that I like: Rarity's art critic outfit, Rarity's Dress 2, The Gala dresses, and Applebloom's tablecloth dress. XD

Favorites:

Dash & AJ at the Gala
Rarity's "candy cane" dress!
Fluttershy's modeling ones
Art critic Rarity (good look)
Wonderbolt Dash
Winged Rarity 8-O
Fluttershy & Pinkie and everyone else at the Gala, including Luna x3
Trixie's...okay, um, I love 'em all. They're either adorable or gorgeous or both, and Rarity, who designed and created the majority of this stuff, is amazing. She just knows style, and her friends, so well. :3

I love all of Fluttershy's dresses (including Gala) but I ADORE RARITY'S ART CRITIC OUTFIT!!!!!!

Yeah me too

All of them are GAY!

^Wow... Seriouslly, what is up with you? That's just uncool.

Yeah uncool dude

why why why i neeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee­eee­eee­eed me~!

:3

SOO KAWWAII!!!!!!!!

Indeed

Oh come on Emmylove786, there must be at least ONE you like.

What about you, you pick (I hate them all)

^I don't really know why I did that. I guess I wasn't thinking about what I was clicking!

Ohh well that's ok

I just love Twilight's Gala outfit. I'm not sure why, but I do.

Absolutely adorable!

ALL OF THEM!!!!! They are all awesome! I just can't pick.

And the Fluttershy fashion outfit.

I can imagine the animators having fun drawing her like this. It's perfectly sophisticated for her, but also a little different to her usual outfits she is seen in. Awesome!

I once wore a dress like that in Animal Crossing........................... Don't judge