Ooh, what a toughie... overall there are four I'd love to have, and for the following reasons...
*Razor Leaf: One of my all-time favorite moves. There's something quite entertaining about manipulating leaves, making them razor-sharp, and slinging them at foes with the chance to hit a vital spot (AKA critically hit).
*Psychic: Another of my all-time favorite moves. It's the ultimate telekinetic power in Pokemon, last time I checked, but I could be wrong.
*Recover: If I ever had a superpower that I could choose, it'd be a tough choice between healing powers and psychokinesis. Overall though I'd love to have the ability to heal wounds with ease, especially on others.
*Aura Sphere: Yet another A-TFM. I like the concept of spiritual energy and being able to use it so destructively can be helpful in dire straights. It's a shame there's no HP-healing Fighting-type move last time I checked other than Drain Punch...