Caffeinated,
It must be a few years since you used Linux. Apart from some games and specialist programmes I'm not sure what you would want to do which you can't do in Linux.
OpenOffice.org will run all your M$ Office stuff, and save it in M$ format as well (or export it as a PDF if you want). This probably makes it more M$ compatible than M$ Office itself as it will run from version 97 to current. I know people with M$ Office that are having trouble with backwards/ forwards compatibility problems.
GIMP is a programme similar to PhotoShop, but free. Is it as good as PhotoShop? Probably not, but it will do everything most people need, plus a lot more, and it is cross platform.
There are many web browsers including Firefox, Opera etc. There are a plethora of web writing programmes and tools, including web photo album makers.
Data Bases abound.
I can watch DVD's from anywhere in the world without having to worry about regional coding. This is important to me as I have family in Europe and Australia and so get DVD's from around the world.
I could go on and on and on, but I won't. I have used M$ Windoze in every format since Windoze 95 through to XP and still have computers with Windoze 2000 and XP. However, I find that I do everything I need on Linux and only use Windoze to help the spousal unit with her work stuff.
I have one computer (AMD2800, 1 Gig Ram) which has both M$ XP and PuppyLinux. Believe me Linux is much, much faster. It is like getting off my 2006 T100 and getting onto my RIII, if that gives you some idea.