What are the top 10 cryptocurrencies to watch in 2017?

As a keen observer of the cryptocurrency market, I'm curious to know which are the top 10 cryptocurrencies that investors should keep a close eye on in 2017? With the market constantly evolving and new players emerging, it's important to stay informed and make informed decisions. Can you provide a brief overview of the top 10 cryptocurrencies to watch this year, highlighting their unique features, potential for growth, and any challenges they may face?