Seiya Kou / Sailor StarFighter is my #1 favorite anime character of all time. I've seen a lot of anime and I like a lot of characters, but Seiya continues to be the one who I empathize with the most. So if you draw him/her well, you can expect a few faves from me.
Sailor Moon was the first series of anime that I got into that I knew was anime (Transformers was my first "fanboy" series, but I didn't know it was anime at the time). Every couple of years, I get back into it. And ever since I saw the Sailor Stars subs (I bought the old VKLL VHS fansubs, before the days of DVD and BitTorrent) I've really liked Seiya.
I really wish there was more art of him/her out there...
Other favorite characters:
Yomiko Readman from Read or Die OVA (not the TV series, which I didn't really enjoy)
Integra from Hellsing
Mizuho from Onegai Teacher
Ludwig from Meine Liebe
Sesshomaru from Inu-Yasha
Captain Harlock/Herlock (however Mastumoto is spelling it these days)
Archer from Fate/Stay Night (He is GAR)