Keeping in mind I have a desktop that I use as a server, storage, back up, and downloading. I work from my notebook as my main computer, I don't travel often other than house to car... car to office. But I do take a notebook with me everywhere I go. 13" MBP with 24" ACD - the advantage being working from one computer, no files to keep in sync. - I'd mount the ACD in my Den on a monitor arm, as that's where I do most of my work. - the disadvantage is working from a small 13" screen when not attached to the 24" monitor. or 15" MBP and MacBook Air - the advantage being I'd have the 15" MBP for use in my Den or when I wanted to work from a larger screen and I'd have the Air for taking along with me everywhere, whether it be to the office, on holidays or the coffee shop. - the disadvantage being juggling files between two computers. or what would you choose?