I know this question has been asked about a million times, but I have one concern. I have used a 17" iMac for the past 5 years. I want to upgrade and get a macbook pro, but am worried about dropping down to a 13" screen. So now I'm thinking would a 15" be better in my situation? I play online games sometimes and do quite a lot of photo/video editing as a hobby. Would dropping from a 17" to a 13" be a big difference in my case, and would it be hard to get used to?