The problems with Q-like powers:
If you can resurrect anyone from the dead, then the value of life is diminished.
If you can accomplish anything by snapping your fingers, then you will never have a sense of satisfaction.
If you can undo peoples' mistakes, then they will learn nothing from their experience.
If you can remove pain and suffering, then you will remove the need for compassion.
If you can become all-knowing, then you will never experience the joy of discovery.
If you can make yourself immortal, then you will suffer the loss of more people than anyone else in history.
If you set yourself up as a super-hero, then people will respect you only for what you can do, not for who you are.
If you change a significant event in history, then everyone conceived after that date will have a different chromosomal make-up and the present-day population will be completely different.
I think I'd make myself fluent in all languages, then do some "invisible observer" time-traveling to discern the truth surrounding historical events, and in the present-day, jump around in various disguises just to have conversations with all the interesting people in the world, trying to shape the future by persuasion only (possibly visiting people in their dreams instead of physically).