Sticking with Microsoft
Most of us who are still concerned with earning a living really have no choice but to stick with Microsoft, because as great as Linux is, every once in a while we run into something that just isn't practical to do without access to a Microsoft machine, and all too often, even Apple won't do. Windows 7 imposes the fewest changes from XP, and it requires a lot less hardware horsepower to run well, so it's the obvious choice, at least for me.
But, one nice thing about the rug being pulled out from XP and it's users is that there are now oodles and oodles of machines that used to run XP that are now being offered for a pittance on eBay. I bought one myself, and installed Ubuntu, and now I have a nice, reliable backup. It can't do everything, but it can do lots.