You know this thread is going to turn into a flame war between Windows supporters and Linux supporters.
The truth is linux is more secure and if you know what you're doing it's a great choice. It all really depends on the distro you decide upon, however if you're totally new to linux I'd recommend Ubuntu. My personal linux choice is fedora or andlinux, but I was able to successfully teach my 12 year old brother to navigate Ubuntu and use it for day to day tasks. Mind you I installed Crossover which allowed me to install MS office and a couple other Windows apps. The problem with Linix though is that people are stuck in their ways and dislike change.
I personally have no problem with Microsoft, nor do I find their products bad. I'm a windows user and I have no problem with it, save for the occasional hiccup though I kind of expect that using beta software. Microsoft makes fine products and in the beginning they were pretty good IMO. However over the years they have expanded and gained enough marketshare to the point where they are the standard. Then they got complacent and things went to hell. They have a lot of talent, though they don't use it in productive ways. Though now that opensource is gaining on them they're being forced to innovate and create more stable products which can only be good for us, the end user.
Now on topic: Steve stop watching so much internet porn and you shouldn't as many viruses. :3 Most likely now you're going to have to reformat your hard drive.
-Written in IE8 on Windows 7 Beta.