RPMS,
I didn't realize that the paint became chalky after a while--bummer! The things i have to learn the hard way...
Owen, polyurethane paint is really tough, but it's also hard to rub out. I think that here in CA, most, if not all, of what you'll find is polyurethane or good old enamel. After reading some about this topic, it looks like polyurethane for me anyway.
Davy