i cant decide im thinking more of MArio but i do love first person shooters what would be bigger

Halo 4 because I thought the trilogy ended with 3. A surprise tetrailogy twist would be interesting.

Halo in USA, Mario in all regions...

It depends on who you ask, but Mario is already confirmed in the works so I would say Halo by process of elimination.

A new Halo game featuring Master Chief would receive more attention.

Depends on what Mario game you're talking about.

We all know Halo 4 is coming. Or at least some new Halo.

However a new Mario platformer would be the first time Nintendo made more than one per console in over a decade.

Master chief in a new Mario game! or vice versa

to the usa halo, everywhere else mario, not by much though halo is popular in Europe, to me halo is very good but mario platformers are my weakness.

Neither game would be a surprise. And both games would generate huge hype on their respective consoles.

And probably huge sales

a new mario game kinda like galaxy but not galaxy