Since I'm already accustomed to the weight, and carrying a book or too with me all the time, or my iPad... weight argument is moot.
I'd get more benefit, and it'd be cheaper... to just upgrade my current setup with a 512GB SSD, rather than going with a current model Air.
(because I wouldn't be buying anything but a fully-loaded top model)
It's too wimpy with the stock setup, imo.
I moved to a Sandforce based SSD. Night and day difference.