From a manga, probably Aya Toujou or Tsukasa Nishino from Ichigo 100%. They were the only two girls that felt real to me. Found it hard to root for either one.
From an anime, it's probably going to be Kagome from Inuyasha. That second movie, The Castle Beyond the Looking Glass just sealed it for me.
Kurumi (Steel Angel Kurumi) it was a long time ago, but I just thought a girl that would do anything for her master was the most attractive thing ever.