I would go for the linux option as well.
If you want to see what its like I would recommend Fedora 10 make a live OS on a memory stick and boot of that and have a play with it.
The Perfect Desktop - Fedora 10 (GNOME) | HowtoForge - Linux Howtos and Tutorials
If your not linux savy this article will walk you through getting all the software you need.
I used to earn a living off dealing with MS and since NT it has become more and more a pain in the arse to not only maintain but also to support.
Just because LINUX has this horrible UNIX thing sitting behind it, these days its just as easy to point and click as any MAC or Windows operating system. You really don't have to get into the nitty gritty command line stuff if you don't want to. IF you do there tons of advise on the net about how to do what ever you want.
If you don't pay windows games and just want internet and office applications, some sort of photo editing and entertainment watching it is more than sufficient and free.
My little aspire one sitting in front of me with Fedora 10 has 30 odd DVD's ripped onto it, a load of music, all the harry potter speaking books. A pair of usb speakers in my bag and it still has 50 GB free. And cost 200 quid new. The equivalent Windows version was 300 quid and after having played with one it seems way way slower than my linux OS.