I like linux for older machines that I don't have to rely on. Not to say that LInux isn't 100% reliable, I just havn't used it enough to put all my faith in it.
However I absolutely love the fact that Linux breathes new life into older computers. I installed it on an old mac, that previously had mac os 9, and now it runs MUCH faster, and is able to actually run current software and browse the internet just like my other machines. Now, when I see someone throwing out an old computer, I rescue it, install linux, and either use it or give it away to someone who needs it. I recently built an internet terminal in my kitchen using an old computer (which i hid in a closet, running the wires through the wall) hooked up to a wall mounted LCD. Everyone that comes to my house thinks it's so cool, and are amazed that it was basicly free.