Reason: I can't remeber I have been using it for quite a while, most likely curiosity.
Pros: great for LAMP apps, I have been testing different open source CMS and other similar open source products, much easier to do on a Linux box, than uploading to a server. If I could fully switch I would, I think it handles updates much better than windows. I love it's responsiveness too, much less of a resource hog than Vista or Xp
Cons:I have no issues with driver on my current config. The only con for me is software, if I could get full alternatives for all of the software I use, I would switch over to Linux completely. I would love to see Linux really come
fully into the mainstream OS market... it's getting closer... but not quite there yet

So I have a dual boot and use Linux when I don't need windows.