I think the reason people will continue to use Windows rather than Linux is the relative certainty that any peripheral you buy will work with Windows. This is because if you're a hardware manufacturer, and you're only going to build one driver, it's going to be the Windows driver.
I use Windows XP. I can plug in the newest blackberry, the newest iPhone, my Hauppauge HD PVR, my logitech webcam with integrated mic, my canon camcorder and point-and-shoot, my son's speaking bear that downloads custom songs, my eSata card interfacing with external hard drive enclosure, my network all-in-one HP printer/scanner/fax, and anything else I choose to pick up off the shelf from Newegg or Best Buy.
Before you post telling me how you can run all these things on Linux, please understand that with Windows, I get to use the manufacturer's drivers, which is what the hardware was probably developed and tested with. I don't have to wait for the reverse-engineered open source version, or the crippled Linux beta driver from the manufacturer. I don't have to worry that the integrated mic on my webcam won't work, or that all the fancy features on my wireless mouse and keyboard are not supported by the driver.
Again, it's not that you can't get any single one of the peripherals above to work with your chosen flavor of Linux, if you try hard enough (maybe). It's the fact that I *know* that any current or future peripheral (with all its features) will be immediately supported by Windows. There's no such guarantee for Linux.