Umm, Answering the what, 6 year old who has made the thread, I would perfer Time Control. I would just go around and stop time and punch people in the face and then resume and they'd be all "WTF! Something just hit my face!" and I would be like 50 feet away laughing.
ahem:
Flight: Well that could be cool. But if you had to pick your one and only super power in your life I don't think it would just be flight.
Super Speed: A nice idea, But when you started walking your body would be moving so fast, Either you would be killing yourself by your own spasms, Or your body would simply disintigrate into a pile of ash due to the velocity you are at. Either would be bad.
Mind reading: Yes it would be cool, But useless pretty much. This is more of a "Wow look friends! I can do this ooo!" skill more than it is a "Omg, I can do anything I want and take over the world with this!" skill.
Fireballs: Umm, The point is, Shoot fireballs from where? Out of the palm of your hand or something? A, that would be WAY to hazzardous, and B, If you shot out fire wouldnt your hand set on fire too? It should be called Suicide Fireball. And unless you're in a war or something that's kinda useless.
Super Strength: Theoreticcally this would be a good idea. Reality wise, No. The minute you got this power you would die of a heart attack.
Invisibility: This is really the only good skill you suggusted. You would be able to sneak by virtually anyone, unless they had thermal heat goggles. This skill is pretty good, but not as good as time control. Just my 2 cents.
And who the hell would want to talk to fish? That's bull.