Really want an MBA 13 due to the amazing battery. I currently have a 17.3" Windows laptop at home (i7-3630QM, 650M, 840 Pro), which is about 4kg in a bag. Now I'm looking for something lighter - MBA seem to fit the bill. I want to set it up with an external display at home / office - and carry it around for work. Would pretty much use the MBA for email, surfing, movie - my current laptop is a bit heavy / overkill - so I'm wondering would the i5 MBA 13 good enough? I can't really stand stutter / lag.