What are the most popular crypto currencies after Bitcoin?

I am trying to determine which crypto currencies are the most popular with the assumption that Bitcoin is the most popular one.

This question is up to different interpretations because “most popular” can be viewed many different ways and that is why I am here asking this question. Most popular could be based on the most real world use, the most media interest, the most valuable, or the most number of people mining or the most processing power used in mining.

I want to know your opinion based on solid facts of the current state of crypto currencies. It could be that another crypto currency is more popular than Bitcoin based on your rank, and I doubt that, but that is why I want the help from experts here.