The only thing I'd be worried about with the OP's usage scenario would be iMovie.
If you want to do iMovie on the go, I could see the 11" screen getting pretty cramped, pretty quickly. Plus, with HD video, you won't get the full resolution of the video on the screen (just a shrunken version).
As one who's edited video in a past career, seeing the video as big as possible, to check for focus, etc... is always a plus. And that would be less possible on the 11" MBA than on any other machine.
That plus rendering time (as the 11" MBA has the slowest processor in the mac lineup - and presumably still will after the SB refresh) will be increased with the 11" over any other MacBook.
Just a thought...