Yukata?.... I don't think it does much for me (which I think should not be the case considering how much manga I read lol). Its not like I think a cute girl would not look cute in one however the odds of me going "ZOMFG, she's GORGEOUS" are not as good as otherwise (and even if I do go there odds are it is because the girl is really cute and I would not even bother to look at the yukata).
I think girls are really cute in yukata and since it's traditional and part of the culture, I approve.
...Although I never have worn a yukata myself, and probably wouldn't. I would look like a huge poser and honestly just really weird.
On other girls, they're great.