I too am thinking about an Air, as an upgrade from a PB12inch. But my summer travels are going to be a lot of backpacking, staying in hostels, loading into busses, cheap hotels, etc, in addition to professional conferences. I don't want to be hindered by a heavy computer, but I also don't want to be hindered by worrying about a shiny, expensive new one either, since I travel fast and poor. And I'd much rather have an old computer broken or stolen than a new one.