The $599 one should be fine, but for an extra $200, you get the i7 which will help with editing your go pro videos.
The i7 will help, and you could add a fusion drive to have SSD and SATA in the machine... Just a thought.
Max out the ram after you get it to 16GB and order it with a remote. You can use front row and browse your music/movies/etc and control it with the remote. It's $20 so why not.