Kefka from Final Fantasy VI, the most badass villain in any video game.

Kratos. Biggest badass in gaming by far. Nobody would f*ck with him and come out alive. Everyone god he's faced has just been brutalised. His variety of weapons makes him unstoppable.

He is actually one of my favorite (definetly fav character in FF series with cloud in 2nd) Villians

Wakka from FF X.

Sonic!!! or Luigi

Weird choice, I know.  I liked him because... idk why really.  He was a posh, english, upper-class bear who only wanted one thing in life.

I actually never got tired of him insulting me for being poor because he was just so consistenly funny.  

Special mention to these three as well:

Ellis - for being a really humorous but weird character that made L4D2 a better game than it already is.

Kai - for being a complete oddball yet surprisingly emotional character which again, made HS that little bit better.

Sweet Tooth - for giving racing games a story.  His motivations never fail to make me go "wtf" like every good crazed serial killer should.

(Compiling this list made me realise I have weird tastes in videogame characters.  I find lead characters very often have very little depth, which leads me to liking side characters a lot more)

edit: And for some reason I completely forgot about this incredible character, so adding her in as well:

Suppose it would be a tie between Squall (FF VIII) and Solid Snake.

The greatest videogame character of all time is Super Mario.

Tom Nook.