I personally like having both desktop + Metro style apps on my laptop because I tend to use my laptop both for casual screwing around and for more focused projects, and Metro style apps give me a nice way of screwing around without it interfering with my srs business project sessions (as they don't run in the background, don't have to close them, don't clutter up the taskbar and desktop window stack, installing them won't have side effects, etc.) Come to think of it, I sometimes browse etc. with my phone at the same time I'm working on my laptop for the same reason.