If a "good" looking person is dumb, that shows through and makes them less attractive. On the other hand, someone who is maybe not considered good looking but intelligent can seem more attractive. IMHO.
I would pick smart, unless by being smart, I have to be scare small children ugly. Can I be smart and just a little unattractive? I would pick beautiful, unless it means I have the IQ of a rock. Can I be beautiful, and at least be able to read at the 5th grade level?