My childhood ones were Strawberry Fair, Dancing Butterflies and Milky Way. I have zero regrets for any of those choices.
Although I am not as fond of white star MW as I am the silver star one. We had both in the UK. Mine was silverstar so I guess I have bias.
As a kid I really was a bit obsessed with Love Melody.
I dunno why.
If the hair is still pink on Up Up and LM, then my least favourite would be Lollipop. She had quite a comic presence but I was never super in love with her even as a kid. But I don't like LM or Up Up faded, so if they're faded, then probably one of them.
And yeah, not so keen on white star MW.
Favourites are Dancing Butterflies and Strawberry Fair, for childhood nostalgia reasons. SF is the only one I have on her UK card though I do have DB's backcard and about five loose ones xd.
...I like both TAF sets. This one because as Ponybookworm said, they're the set we had in the UK (for 2 years -.-)...but I do also love some of the 2nd set (Buttons, NG) for how pretty they are.
I guess my favourite TAF overall (or I should say, "Party Pony") is probably Strawberry Fair though. She was my first, and I still love her. White and red is a combination that always works imo.