Reset Button: if you could...

[Ironbear24]

Bruce Lee.

Mas oyama

Jigaro Kano.

 

[GreenieMeanie]

So you're walking down a street and a blue police call box materializes right in front you, and a nice British guy or Scotsman steps out and says sorry, there's been a terrible mistake, I just saved the earth, but your martial arts skills, muscle memory, and training were *ahem* lost.
He continues:
I will be glad to help you recover new ones as a replacement. Step inside, and tell me three instructors you would like to train under for as long as you like. While undergoing your training I will reset your age to remain at 18, and the universal translator will take care of the rest.

You step inside as you say:

1. Jarrad Arbuckle-- for overall fighting knowledge
2. Craig Douglas--Grappling with guns and other weapons
3. Ed Calderon--weaponology, fighting while in restraints, and other dirty fighting

 

[Monkey Turned Wolf]

I think I missed this thread the first time around. Assuming we're not limited to live instructors/they will be at their peak instructing years,
1. Miyamoto Musashi. Theoretically one of the best swordsmen of all time.
2. Seiko Fujita. The last 'real' ninja. The way the question is written, it sounds like I'd have a lot of time to train under him, and hopefully become heir to his style.
3. Morihei Ueshiba. The founder of Aikido, who must have known enough to create like 10 different versions of aikido as his own philosophies changed.

If I can't create a martial arts empire and become a millionaire, being a verified student of the greatest swordsman ever, the heir to a ninjutsu tradition, and a direct pupil of Aikido's founder, that's on me. And I'd have the advantage of being legitimate, so no guilty conscience.

 

[drop bear]

I would train with Hitler.

Then kill him.

 

[Ivan]

So you're walking down a street and a blue police call box materializes right in front you, and a nice British guy or Scotsman steps out and says sorry, there's been a terrible mistake, I just saved the earth, but your martial arts skills, muscle memory, and training were *ahem* lost.
He continues:
I will be glad to help you recover new ones as a replacement. Step inside, and tell me three instructors you would like to train under for as long as you like. While undergoing your training I will reset your age to remain at 18, and the universal translator will take care of the rest.

You step inside as you say:

Masutatsu Oyama for Kyokushin Karate
Lucio Rodrigues "Lagarto" for BJJ (my current professor's professor)
Miyamoto Musashi for Weapons