Hmm, off the top of my head: SacredFire and Aeroblast. G/S/C Aeroblast is the best.
Roar of Time and Spacial Rend appealed to me until I saw their animations. I was hoping for either one to at least cause a ripple effect in the screen (like how heat distorts air), but they only shoot colorful spirals and circles.
I think I like Aeroblast the most (in Generation 2) and Shadow Force in Generation 4. Aeroblast's animation in all games after Generation 2 was horrible so I only like it's initial animation. Shadow Force is just cool-looking in all games so far.
All of the dragon trio's special moves are fantastic. Especially Shadow Force. As far as normal pokemon go, I really like Leaf Blade. I'm down with anything that raises the CHR, and Grass can always use a good move.