Koga, mainly because I dislike everyone else from the poll. However, my favorite male character (and favorite character from Inuyasha) is Naraku. With his dark, cold, manipulative persona, he makes an awesome villain. Jakotsu and Bankotsu come in very close seconds. I'm also a fan of Menomaru, the main villain from Affections Touching Across Time.
I love SEsshoumaru. i just do. i can go back and watch the third movie with his fight scene against inu (the first one)a thousand times and still cheer just as loud. don't get me wrong, i love inuyasha though...just not as much as his brother.
i have to agree wtih Bankotsu though. i love his personality of "f%ck all!" he's amazing.