I can also safely say that in all that time, I've never once missed having an optical drive. More USB ports would have been nice, but I have a four-port USB microhub that does the trick there.
Some detractors point to the Air's cost versus its perceived low performance. A common point of view: You can get a laptop PC with better specs for less. Yes, you definitely can, but would it be as infinitely portable, as usable, and overall, as reliable as the Air has been for me over the years? I have plenty of PC laptops that see far less usage than my Air, yet seem to suffer far greater problems, from disk failures to screen issues to battery problems and so forth. There's a reason that they're cheaper: They're made with cheaper parts and engineered to meet a very low price point, rather than being engineered to survive.
In the laptop world, you can have only two of the following three attributes: cheap, ultraportable, and reliable. While the Air isn't cheap, it certainly meets the other criteria, and it offers Mac OS X and the power of a native Unix environment on top of it. Why would I need anything else?
As always, your mileage may vary. But for me, at this point in time, there's no better way to interact with the computing world than a MacBook Air. If and when that changes, I'll be all over it, no matter who makes it or what form it may take.
I'm not holding my breath.