Some 98 char have this "lady aura" around them. I am mostly thinking about Kana, Elly and Louise here. There's also Yuuka on her pc 98 outfit, where she wears pants with her long hairs, and she's strongly elegant like this.
I strongly like Marisa on her 98 outfit, especially in PoDD where she looks like a wizard, her dress is long and is purple, and her hairs seems smooth. I love Rikako because she's the only one to have the scientific look, and that I enjoy the scientific thing. I always loved Mugetsu's design, I know that I could say that I love Ruukoto, Sakuya and Yumeko's one since it's pretty much the same thing, but I don't know, her face goes well with her outfit and all.
I like Meiling's outfit, it's pretty. Yakuri in PCB is just omg. I must say that Lunasa on her "black gothic" outfit in PoFV is just so epic and fit well with the personality of the character. I like the simple outfit Reisen have, more the PoFV one where her shirt is white. I REALLY love Medicine' outfit: because it's red/black(and purple/black on her alternate color), and I love these two mixes. Also because she have a little similarity with Rin Satsuki. And she also make me think of a Rozen Maiden, I tend to find that funny.(and some dolls were great in rozen maiden). I don't know why, but I think that Shizuha is wonderful, her dress is actually pretty simple but very effective, she have the head to wear this dress, I don't know how to explain it. You couldn't give her a better outfit, honnestly. Hina have really an impressive one, she looks like a 5th boss, I strongly like her boots, and she have this black/red mix that I really love. Parsee has a great fashion sense imo, pretty original and epic. It's inimitable. Kagerou seems like a singer on her dress, imo, it's really lady like, lol. as for Seija, it's the same as shizuha: simple but strongly effective. Raiko have just a great fashion sense, I love the white color, it's classy and beautiful, so she really stands out in the touhou universe because she have a more modern design.