The problem is that most of the people who can do the coolest stuff also have extreme physical and/or emotional baggage, so if that doesn't apply, I'd want to be either the Flash or the Doctor from Doctor Who.

If that does apply, Wong from Doctor Strange. All of the powers of Doctor Strange, but you get to read books all day instead of deal with a crippling hand disability.

I would be Voltex

Really the only choice is Ditto.  Or something similar, such as Krakha.  That way you can become any character for any amount of time you want before switching to a new one, and get all their powers to boot.  You'd get to ask yourself this question every day rather than just once.  It's the ultimate workaround.

yes

Really the only choice is Ditto.  Or something similar, such as Krakha.  That way you can become any character for any amount of time you want before switching to a new one, and get all their powers to boot.  You'd get to ask yourself this question every day rather than just once.  It's the ultimate workaround.

Couldn't Krahka only use forms/powers she had seen firsthand tho?

Steven Universe.