At this point, it's looking like the answer is going to be selling off the MacBook and (eventually) the Sony and consolidating into a single PC laptop. I have a reasonably powerful desktop for my needs (home-built Core i5 running Win7) and a nice Dell i7 laptop for work stuff, courtesy of work, so I'm mostly looking for a small and light enough personal laptop. I'm thinking I may just go small and cheap and leave the heavy lifting to my desktop PC, so I'm looking at some of the new AMD 'Zacate' E-350 systems that Engadget likes to refer to as "notbooks" -- probably the HP DM1, since it has one of the new clickpads on it.
I considered getting a MacBook Air, but decided not to. Even though they're very nice machines I'd really rather not pay the price premium, and I'm honestly not very enthusiastic about some of the things Apple is apparently doing with Lion. For the OS X-specific stuff I do -- mostly Ruby and Python in MacVim -- I can do it just as well in Linux and on the same platform I'd be deploying it on -- plus I can set it up to dual boot Windows and drop back into that if I want or need to.