MacBook Air, no question. It's fast enough.<p>I came to this conclusion unexpectedly, having lived with a couple of generations of MBP 17", and, tiring of slow laptop drives, got a latest-generation 24" iMac a few weeks ago. (Which is a great balance of disk/CPU speed, size and cost vs the high-end Mac Pros. I had a 30" cinema display on the MBP and found it too large, oddly enough, while the 24" size seems just exactly right, especially when paired with another 23" cinema display for serious real estate.)<p>Then, having passed on my latest 17" to my daughter for some serious InDesign production work (2000+-page concordance), I realized I'd need a portable machine, so got the Air as an after-thought, assuming I'd only use it on the road.<p>Without my realizing it, I had shifted most of my daily work to the Air (email, web browsing, Campfire, iChat, NetNewsWire, Terminal (emacs), etc.), leaving the iMac for only actual development work. (Mostly iPhone development these days.)<p>The Air seems just as snappy as my recent-generation MBPs, and it's a dream to pick up and carry around--more like a paper notebook than a computer. The screen is about the best you'll ever find (LED backlighting), and the CPU core shutdown problem seems to be defeated fairly easily by simply selecting Optimization: Normal in the Energy Saver system preference panel. (I don't think this particular fix is well-known. It certainly solved the YouTube-video-causes-one-core-thermal-shutdown problem for me.)<p>So go with your heart and you won't be sorry. ;-)