I still run an Air (mid 2011) with 4GB of RAM and 256GB. Still great for browsing, lots and lots of text (Word and FadeIn), lots of Adobe Premiere editing on the go and occasional Photoshop and After Effects. I've been eyeing for a new laptop for quite some time now, but I am not in a hurry. This thing just keeps going and I can't justify new purchase yet.
My Air can survive with 4GiB of RAM, but if I watch YouTube videos in Firefox for long periods of time, the thing starts to use 3GiB+ of swap and I have to quit the browser.
I'm on chrome, absolutely no issues at resolutions up to 1080p. Haven't bothered with higher since screen res isn't. I throw video and AE rendering on the machine when I'm out with it, occasional compile with gcc.. damn thing is great. I would love to see newer generation Air come to light. I'd buy one immediately.