I'd say the cowboy...just because they would have hell making him a storyline, and I'd bet the story would be so ridiculous that I'd probably like it!

a monk. because he seem like he would fit into mortal kombat bein that it is a sacred tournament and now that evil keeps comeing he would try to make it back to what it was meant to be.

A monk would be the most logic choice as the best fighter, a sumo would be too slow, what fighting skills a cowboy will have I don't know, I don't think they'd have a priest in such a gory fatality filled game like MK, there'd be complaints trying to get MK told off the shelves, a viking is a bit out of the timeline, they're don't exist anymore do they?

I'd have to say a cowboy. He could have the biggest rivalry with Nightwolf. It'd be like cowboys vs Indians. How good ?

A monk the only thing that would fit I believe.

a Viking..(kinda funny that i say that because i have yet to read the viking thread lol)..
this would be a kool character to play as... maybe w/ all the portal shit and magic.and worlds merging..maybe he gets pulled from the past into the present...i like the whole look..his weapon would be a large axe..the long hair and steel helmet..i like the whole mid evil look..

If it were from outworld, a viking may work even though it would be a stretch. A sumo wrestler would probably be slow and boring, like Bo Rai Cho. A cowboy would be absolutely ridiculous, I think it's bad enough that they have Nightwolf. The best of the ideas would be a monk, of course it would have to be from a different place than all of the other monks.

id love a priest, id love to see a someone on Gods side to kick ass!

Kung Lao and Liu Kang are part of the Shaolin temple, so MK already has monks, kind of. I quite like the idea of a viking themed character myself, some giant in a helmet using a massive axe or club.