1. Alucard (Hellsing). He is in my opinon, the best character I've come across. He's really loyal to Integra, and he packs quite a gun. He fights with no restrictions, but at times, you wish you could tell him it's okay to show emotion. He's really good about trying to hide it.
2. Grimmjow (Bleach). Like you didn't see this coming. It was between him and Alucard, and the vampire won. Grimmjow has this personality that I wish I could have. He doesn't care about serving other people and he's a free spirit. He's really tough and strong and wants to prove how far he can go, and no one can tell him otherwise.
3. Sesshoumaru (Inuyasha). If the world was ending, and earthquakes were ripping up the earth, tornados were devastating the plains, tsunamis were flooding whole countries and a giant twenty mile wide asteroid was on its way to kill us all, this would be the guy standing in the middle of the screaming chaos with this total look of indifference on his face. That is the mark of a man with guts. He would just turn to the bad guy causing all of the pandemonium, gut him where he stood, and then walk away while the castle explodes in a blazing brilliance of wreckage. He's like Gimmjow with no emotion.
4. Kyo (Samurai Kyo). Knowing this guy, he's probably the one causing all the pandemonim mentioned earlier. He reminds me a lot of Alucard, and I think the anime of Samurai Kyo didn't really give him--or the other characters--the credit they deserved. It totally deviated from the manga. But I still liked his voice and his attitude. He pretends to be a man with no ties, but on the inside, he really does care.
5. Vincent (Ergo Proxy). At the start, you get the impression he's a complete wuss and you kind of pass him over for Re-L. But they trick you. Give Vincent a haircut and a few good dark lines and suddenly, he's a new man! Though he retains his meekness, especially around Re-L, there are parts in the series where he gets really serious. I like the color of his eyes too. They really stand out against the dark backgrounds.