How to get around the city?

I sometimes wish I lived in a big city, for various reasons...culture, restaurants, shopping. Then I think, "Well, if I lived in a big city, I probably wouldn't have a car...how would I get around?" Obviously, I would use public transportation as much as possible, but what if I had to go somewhere that maybe public transportation didn't go to? I guess in that situation, I could hire a car service, like LGA car service. They offer service in and around New York City, Brooklyn, and New Jersey...safe and reliable. Sometimes, it seems like that might be a better option than hiring a cab.