My humble kit for the last couple of years. A Canon 550D and a Macbook Air. I've been considering an upgrade but honestly, they have served me well, light to carry on my various motion graphics adventures, and I'm still amazed by what these things can do.
I tend to use an external monitor at the offices where I freelance. If a monitor isn't available I can hijack other Macs as a monitor with the thunderbolt cable. Handy dandy. :)