[Afro]

Boxing is your best friend.

but ya as stated, Wrestling is the most effective to know in MMA I believe because you learn takedown defense, and takedowns and any standup fighter.. as dangerous as standup fighters are if they cant defend a takedown they pretty much lose.. see Arona-Silva for an example. Wrestling is probably the easiest to learn, ive never wrestled but I got a handful of friends who have and they say learning the moves isnt the hard part even though they learn about 3 moves a week and practice on them.. the strength and conditioning plays a bigger factor in there wrestling.

I'd start off with Wrestling, move on to boxing/kickboxing/muay thai, then end with BJJ.. gotta have a complete game.