I am a Navy man so my opinion is somewhat influenced.
But, the SEAL?s of course! They are the BADest!
When a future SEAL gets done with BUDS school, he goes off to phase two of training, which is Underwater Diving. You know they say (could be a tall tale) that during UD training, they actually get drowned and learn to breath, with some substance, just like they did in the movie Abyss. ???
But anyway, then there is phase three, which is called Completion Phase. Over the course of a year, the go to Ranger school and learn to jump out of planes (as high as 30,000ft), then Marine Recon., and Delta-Force Command. Then they?re full-fledged SEALs.
But don't forget about the Black Beret's. There are Green, Red, and Black Berets (in that order of bad-ass-ness). Sometimes you here things about the Red Beret's but you don't and probably will never here any thing about Black Berets. (in the Media)
So that's my vote. SEALS!
GOD BLESS AMERICA