Frank Richie recons that Jesus would use open source.
I’ve used Unix some, but not a whole lot. I do know one fellow who did support it on one site, and he made a good point – open source is free up front, but if something screws up you’ve got to get the guy who set everything up to sort it out. And that guy may find his time very valuable… if he’s even in the same country that is.
I have a better way.
1. Purchase a computer like this one, with specs plenty enough to run XP, and with a license stuck on the side. For $1 reserve, that’s a pretty cheap computer and windows is thrown in for nothing.
2. Install Open office, AVG Free virus scanner. The essentials – free.
With web browsers and most email now on web interface, what else do you need?
Something should go here, maybe later. 
If that does the trick for you, go for it. But Linux is also a great option for others. With your XP machine you’re reliant on AVG to protect you from viruses, while with Linux you’re pretty well immune to them. Furthermore there may be a wider range of quality free software available for Linux (depending on what area you are talking about), simply due to the fact that the open source developers are using Linux and build for that by preference.
It completely depends on your own needs. XP is good enough for many people, if you can get it cheaply. But I personally wouldn’t touch Windows with a bargepole, and exclusively use Linux now (shifted from a Mac 6 months ago and haven’t looked back).