"What's up?".... The Best Phrase to use with Peers?

Today, I was randomly thinking about a certain phrase that is commonly used.  This phrase would be "what's up?", which is commonly used between people in school who are greeting each other.  I personally have never been a fan of this phrase for a rather simple reason.  Basically, I do not know of a proper way to answer the question.  Sure, the phrase is basically used simply to say "hi" to a friend, but I still find that saying "what's up?", as an alternative can cause some awkward moments.  When I respond to the phrase, I almost always say "not much," or "nothing."  Many times, conversations can end after a person responds to this phrase with a simple answer, like "not much."  Personally, I like to use different phrases such as "how is it going?", or "how are you?"  The phrases may not seem much different, but I believe that these phrases open up a conversation better than saying "what's up?"  Overall, I know people will continue to use the phrase "What's up?", including myself, but I will try to make an effort to use other phrases in situations in which I believe that other phrases will better open up a conversation with one of my peers.