Takamura from "Hajime no Ippo", Kenpachi & Gin from "Bleach" [that eerie phukkin' smile, ugggh], the Twin from "Monster", Izaya from "Durarara". there was also some1 from "Robin The Witch Hunter", but i'm blankin' out right now.
Mine are Creed Diskenth (from "Black Cat") - he sometimes acts as gay, but still has badass personality and charisma, and Hazama/Terumi from Blazblue. Also Dio Brando(Jojo) and Jedah (Darkstalkers) are badass psychos of course :)
