The MacBook Air is the only computer I use. I'm using it for photo editing, digital painting, light-to-medium video editing/encoding, and daily things like web browsing, email, music.
I went with a Mid 2013, 13-inch, 256 GB, 8 GB RAM model and I'm loving it. The storage isn't really an issue for me, but I've gone ahead and purchased one of those
Nifty MiniDrives and I'm carrying my entire iTunes library on it, saving me 64 GB of space on the internal storage. I also have an external, USB 3, 2 TB Hard Drive as well for storing my edited video.
The 2013 MacBook Air is a great machine.