Yeah, there'll always be 'the next generation' of product - and if you wait for the next best tweak to a product, you'll never buy.
Meanwhile, I really don't see the value in Retina - it sucks power and, really, for what you want to do, its hardly needed. Apple's screens (that is, the ones that don't arrive with weird blue or green auras or peculiar lines running through them) are generally very clear and crisp - Retina, arguably, is simply another marketing ploy to be 'better' than the last model or anyone else.
And finally, save yourself some bucks (routinely 15% or more) and visit Apple's Refurb page in their Store - get an Apple-certified Air with all the features and warranties from there.