Egyptians went to the polls Wednesday to choose their first freely elected president in a vote that could end 15 chaotic months of military rule and define the future of political Islam. It was a new climax in a cascade of scenes that would have been unthinkable just two years ago, when election days meant that state television would film former President Hosni Mubarak walking a red carpet to his special polling place in a predictably fraudulent plebiscite. But on Wednesday, millions of Egyptians waited patiently in long lines, often holding scraps of cardboard against the desert sun, and debated with their neighbors over which of the five leading contenders most deserved their vote. “It is like honey to my heart,” said Mohamed Mustafa Seif, 36, an accountant voting in downtown Cairo. “For the first time in my life, I feel like I have a role to play. My vote could possibly make a difference.”