Um, if you've seen the "Top Five Anime Badasses" thread...it's basically the same thing, yo.
5:

Ocelot, from Metal Gear Solid 3: Snake Eater. At first, Ocelot was something of a cocky loser who kept getting his ass kicked by ole' Snake...but, later on in the game, his mysterious role, attitude, and his insane revolver tricks definitely earn him the #5 spot. Too bad he turns into a sadistic old dude later on in the years... :(
4:

The Truth, from Grand Theft Auto San Andreas. He's a hippie who's made close friends with virtually every powder, pill, and needle known to man. And yet, he's still alive and kicking enough to offer his immense wisdom of all shady government activities involving aliens, has enough of a heartbeat to stuff half of Mexico-worth of weed in his van, which he dubbed the "Mothership", and to top it all off, keeps a grenade launcher in the Mothership which he planned to turn into a lamp some day. Giving him the fourth spot on my list is just....good karma.
3:

Sho Minamimoto, from The World Ends With You. So, he's a little bit crazy, and has a fetish for everything math related...and to top things off, he creates random pillars of junk everywhere he goes. But underneath all that, he's a twisted super genius, backstabber, heartless and cold, and has equally crazed ambitions. He would be just a downgraded Ocelot...if it wasn't for the fact that he's crazy strong; strong enough to get the attention of a Fallen Angel.
2:

Vergil, from Devil May Cry 3. If you've played DMC3...you'd know why he gets this spot. If not, then go play the game! :[
1:

Shiki Nanaya, from Melty Blood. I doubt many of you know who he is...or even what "Melty Blood" is (a badass PC 2D fighter), but...he's definitely my #1. He's Shiki Tohno's alter ego, more or less... Where Shiki is a timid teenager who's too nice for his own good...his alter ego Nanaya is a cold, calculating ruthless assassin who has speed and accuracy on his side. Where Shiki struggles staying alive with an opponent, Nanaya can instantly kill that very same opponent with a smirk on his face, and sarcastic remark to top it off. It might be a good idea if some of you guys check this game out...