I vote for Smoke and Scorpion.
Scorpion, simply for the sake of it. He is just a cool, badass character. He looks amazing, has white eyes, is skilled and so on. Damn badass mofo right there.
When I got into Mortal Kombat (during Mortal Kombat 2 and few games after that one) I actually liked Kabal and Noob Saibot the most. Kabal, because he was always so fast and Noob Saibot, because I liked his shadow-like abilities.
But then ... this happened:
I actually really liked the two MK movies and that scene. Damn, I had goose bumps of death during the entire fight scene. Smoke was so badass and especially his crazy ass abilities.
Then MK9 came along and they executed the character so well with the invisibility, the smoke-bombs, the smoke-teleportation and ... his best tool ... the god damn teleportation above you and smack your world up from above-stomp. Nothing in MK9 looks as awesome as that attack.