I'm going to go for someone non-Supernatural again, just because I can't pick a favorite out of the recurring female characters (though, probably if I was at gun-point, I'd probably say Ellen).
Akira from Mai-Hime.
Mai-Hime is actually a really good anime, if you can get past the first 8 episodes of anime-cliches. And I think the Akira+Takumi romance is the sweetest thing - who doesn't love a good gender-role reversal?
Special shout out goes to Shiris from Record of Lodoss War - because she loved Orson (like me), and was a strong female character who eventually ruled a country. Plus, I met a girl who looks just like her in real life (and has a similar name), and I won't go into details...but that relationship was AWESOME.