The real question is, would you have any regrets if you bought it now and they came up with the new one just past your 30-days return period, or not ?
I would wait, if only because if the new one doesn't fit my needs/wants, I will be able to buy the current one for less than I would now.
I bought my mid-2012 MBA in May 2013. Just one month and one week later, they got the new one out, with 2x the battery life. I really really hated that - especially since the mid-2012's battery is dismal. But hey, I survived and I still use it every day. I would have pulled the trigger long ago if not for the Retina rumors. So i'm waiting, so I will be able to CHOOSE, and not regret my choice.