The Gorton Fisherman would win. Trust him.
I assumed it would be similar to a fight between him and a lion where they both end up winners.
The answer is the Old Spice Guy if played by Bruce Campbell
[From Army of Darkness]
“Ash: [cocks shotgun and points it under Evil Ash’s nose] [nods head and shoots him] Ash: Good. Bad. I’m the guy with the gun. …”
Muscle guys and interesting men have no chance. 
I say The Most Interesting Man would win. He’s older and has had more time to learn dirty tricks.
Which Old Spice guy?
The Old Spice Guy can make diamonds magically appear in his hand, which he throws at Most Interesting Man in an attempt to dazzle him, but MIM has little regard for such petty distractions and, with his team of loyal Japanese snow monkeys cheering him on, give OSG a sound thrashing, after which, mutual respect gained, they go to a nightclub where neither need serve as wingman because the ladies are all over them.
I’m not sure they’d even get a chance to fight. Before they began, the various women surrounding them would probably start tussling with each other, hair whipping to and fro, clothes tearing, pillows flying. And in that case, we’d all win.
I’ll drink to that! (Pours Dos Equus into a frosty mug, tops it off with a foamy head of Old Spice shave cream, drinks it down.) “Four hundred qatloos on the leggy redhead!”
Well, because they are who they are, they’re totally hot and irresistible. They’d obviously stop fighting and have sex with each other.
But since they are who they are, it totally wouldn’t even be gay. Not even a little.
He can bone another dude, enjoy it and remain a negative-6 on the Kinsey scale.
Stay thirsty my friends.
Mr. Clean would wipe the floors with either of them.
I’m amazed that I’m the first to say my hope is that they would off each other, thus making contemporary television marginally less asinine than it is.
Hey, look! It’s the tiredly predictable backlash, right on cue.
Ash was written to be completely incompetant at everything except killing the Evil Dead.
The World’s Most Interesting Man once punched a magician…that’s right…you heard me.
The right look should suffice to defend against the Old Spice guy. Old Spice better start beefing up his obituary.
That assumes that these two commerical guys are more assinine than TV in general and that if you removed them the assininity level of TV would drop. I highly suspect it is actually the other way around and removing them would make TV on average just a bit MORE assinine.
I wonder if there’s anyway we can involve Flo the Progressive chic in this Battle Royale.
Missed it by that much:
A little hair of the horse, huh?
I don’t think they would fight. They’re too cool for that.
She’d be off to the side taking on all comers.
Neither one could even touch The Orkin Man!
Good luck with that. You’d need a lot more killin’ before anything would be noticeable.
On the OP:
“I don’t always fight other advertising icons. But when I do, we both win.”