The New Your Times (free registration required) reports that laptop sales surpassed desktop sales for the the first time in May. This doesn't surprise me. Laptops are more convenient. I think laptop users are potentially more productive. I've used a laptop exclusively for years. What's held laptops back is their price/performace ratio. But now, computers are getting fast enough that people are finding that reasonable priced laptops are "fast enough." And as the article says, laptops are sleeker and sexier than clunky desktops.
When we talk about the move to mobile computing, we immediately think of phones and PDAs, but tablets and laptops have a role to play in that story as well. Whenever I see people using tablets (admittedly early adopters), I ask them whether they've given up their PDA and their desktop and transferred all their computing to the tablet. The answer is usually "yes." One even tell me that buying a tablet has led him to purchase a sheet fed scanner so that he could just get all the paper people send them into their tablet and be done with it.