Timewise:
I don't like the clown costumes, mainly because I don't think magicians should act like clowns. I don't buy into the idea that kids magicians have to behave like a buffoon to be entertaining.
Start with the character you want to be and build the costume around the character -- not the other way around. Think Willie Wanka, Mary Poppins, the mad hatter, the Cat in the Hat, Dr. Who, Dumbledore, Gandolf (when he is doing tricks in the Shire), Dr. Brown from Back to the Future, any Robin Williams character, etc. Figure out a movie character you are like or develop your own character. Then figure out what to wear.
Now, your effects need to match your character or vice versa. Gandolf would never perform the magic coloring book and Mary Poppins would never do an arm-chopper (although I could imagine her singing "a spoonful of sugar helps the arm get chopped off...").
To perform, I wear a black suit with a French blue button down shirt (see my profile picture and imagine it with a darker blue shirt). It is professional and stylish -- sort of a reflection of Robert-Houdin's idea of a magician's wardrobe reflecting the style of the day. My character is a story teller -- someone who invites you to join them in their imagination and play. My character is more reflected in how I act. My voice has a playful excitement to it, my eyes have a mischevious glimmer to them, my actions have a deliberate energy.
Figure out who you are as a character and then figure out what that character would wear.
