I'm running swappable hard drives in my main IBM quad-Xeon worstation. One hard drive is Suse 10.3, the other WinXP Pro.
I absolutely love the Suse Linux, but it by no means an easy system to install and set up for hardware. As much as folks love to bash Windows, it still is truly an Everyman's OS. Linux has a long ways to go before it exits the domain of the computer geek.
The reason Mac users have it easy is because they're basically a sole-source system, drivers and apps don't have to be written to support a myriad of vendors and configurations. Windows could be a lot more streamlined if they didn't have to support all those parts and pieces.
It's already been streamlined in some circles. I've played with XP Lite and Tiny XP - they're great when you want optimal performance sans all the bells and whistles. You also have to know what you're doing to build a Tiny XP install. Unfortunately, as an Everyman's OS, Windows XP and Vista are still trying to be everything to everybody. They have to, including Ma and Pa Kettle, who just want something they can plug in and turn on, without having to upgrade, install, or tweak anything. Short of going for the aforementioned sole-source Mac, they're going to either buy XP or Vista, because that's what they're going to find at WallyWorld, along with the software titles. Unless they have a geek in the family or know one, they'll go no further.