On topic though:
IMO the 720P resolution is horrible for doing any real work. Browsing webpages, email, etc are fine. But anything more, and you will run into trouble.
If it will be your portable then the 720p screen is fine. If it is your main computer, then depending on your usage, it may be a bit limited.
In my own experience, I used to own a black macbook before (1280 x 800). Although, I was initially very excited about the beauty of it, I quickly got annoyed with the tiny screen. For me, it just became a very expensive internet/email machine.
I recently upgraded to a MBP 17(1920x1200). And this, I can say, is a pleasure to work on. It does weigh 6.6 lbs. But thats only 1.1 lbs heavier than my black macbook, so I'm good.
But it seems to me that the 13 inch MBA is a good balance between size, weight and screen estate.