How can we bring solar power energy to our streets?

I was having a debate with my friend about ways to make the environment better and to have a better energy reliance than oil. One idea that was floated was to have every street lamp based on solar power (with backup electrical grid power in case it rains or something) anyway, here was the debate which we need your answers to: Is it better to have a solar panel on each street light OR Is it better to keep the street lights as they are and just install solar panel hubs around the city that feeds into the electrical grid?