People from different regions may use different ways to greet each other. I think 你好 may be the most common way to greet an acquaintance or a friend, but between close friends or family members, we don't use it. I think in the U.S, you don't greet your parents with hello as well.
您好 is only used in formal situation or greeting a person who's obviously older than you, sort of like "usted" in spanish.
As for 你好吗, I've never heard any chinese people using that sentence to greet their friends. It's only a translation of "How are you", and we don't use it when we see our friends.
So in conclusion, 你好 is the most common way to greet people, but once you became friends with them, you don't need to use these words, just say 嘿（hei）and smile will be enough.