It is really surprising how the Linux kernel has evolved from a mere hacker's project to a robust, stable and device friendly piece of software. At one time it was imperative that one fire up a terminal and tinker with the underlying code or at least type a series of commands to get even simple things working such as burning a CD or playing music and so on.
But now most Linux distributions have become so easy to install and use that even your grandmother could do these tasks with little help and without ever touching a terminal. The plug and play devices have become truly Plug and play and works flawlessly - be they USB devices, Ethernet cards, sound cards and what not. There is very good support for most hardware devices you find in the market baring a few. It also helped that many IT behemoths of the likes of IBM have taken active interest at Linux and have been pouring in money and developers in promoting and sustaining the project.
To underline the advances made by Linux kernel, here is a very good slide show which spells out the Myths, Lies and Truths about the Linux kernel, prepared by Greg Kroah of Novell SuSE Labs.