I also have a 13"/8gb/128gb MBA. I decided to opt for 128gb to sort of force myself to be diligent about not letting old and useless files accumulate on my drive. On my old laptop, I was so bad about managing old stuff and the majority of my drive was just filled with crap. I figured once I trained myself to manage my storage well with the 128gb, then I'll get a 256gb drive and swap it myself. Although as of right now I still have 60gb free on my drive. But I would like to boot camp Windows 8, so I might switch to 256gb sooner rather than later. And now I've been rambling, so I'm done now.