I saw this post on Chase Jarvis's blog today, which quickly made some interesting points about the different and constantly changing skills needed to be an assistant for one of the top commercial photographers in America.
It boils down to a simple premise; nobody can know everything, but being willing to learn is an invaluable tool.
His blog is great for learning about new equipment, inspiration and techniques, as well as behind the scenes videos and stories about his escapades as a successful shooter. He also made the jump into doing film productions as well as stills, which these days is becoming an expected service from many clients.
You can view his extensive photography portfolios here: http://www.chasejarvis.com/#mi=1&pt=0&pi=2&p=-1&a=-1&at=0
And the video projects here: http://www.chasejarvis.com/#mi=1&pt=0&pi=3&p=-1&a=-1&at=0
Definitely worth a good look around if you're keen to learn something new.