What's funny is that, while they're both smart, Tony graduated summa cum laude at MIT with his double masters degrees, after entering undergrad at age 15. Then took over a company too. But he doesn't have Lucious Fox to make his little toys.
And that is why the Joker is quite possibly my favorite villain of all time . He isn't evil for power or money or revenge or for some sick idea of peace he has. He's doing it because he just wants to see people suffer and be hurt, and he has no remorse in doing so. I think he's probably the ultimate villain ever.