Arguably the most famous bastion of baldness in superhero comics, Professor Charles Xavier lost his hair when his mutant powers emerged -- quite a trade-off. Since then he's displayed his bald head with pride, even if it made him look older than he actually is.
Spider Jerusalem didn't go bald, he made a choice. In the first issue of Transmetropolitan he's shown with a Alan Moore-like cascade of dark locks, but shaves it all when he descends back into modern civilization.
Uatu the Watcher
The enigmatic Uatu the Watcher never had a chance to style his hair; his entire race is born to be bald. His father once carried a mean-looking goatee, but Uatu has never been seen with even a 5 o'clock shadow. For Uatu, his baldness propagates the alien "other-ness" of his persona as a hands-off observer of the human race. He's set to be murdered in next month's Original Sin #1, but should he ever come back, perhaps it will be with a stylish new 'do.