This article from Reuters Business News reports that Dell is considering offering GNU/Linux as an alternative to Windows on it's personal computers. Of course this is great news for free software.
I think there are at least three major factors that will make this a huge success.
1) The price will be lower. Dell doesn't report how much of the purchase price goes toward Vista when you purchase a new Dell computer but it's probably not as low as say Ubuntu with a price of $0. And, for lots of users, price can easily be the deciding factor. No doubt, Dell will offer direct or third party support which will incur a price, but it will be an option.
2) The barrier will be lower. Right now, if the average mom and pop wants to run GNU/Linux on their computer there are a multitude of options and although it's dead easy to install, there's not much reason to because Windows is already installed. The switch from Windows to GNU/Linux is complicated by the fact that the user has usually already created documents and folders and they often have no idea how to move that data over to a new OS. Unless they have a kid who is a geek, the barrier to switching is pretty high. If, however, the OS comes preinstalled and mom and pop just start working with the new GNU/Linux box and creating their documents there... no problem. And, in fact, there would then be a barrier to switch back to windows, for the same reason.
3) No viruses. PC users can join the MAC crowd enjoying virus free operation of their PC. Security with GNU/Linux is just so much higher that there's no need for anti virus software and all of the complications and expense that goes with that.
4) Okay, I said three but here's one more. It's good for you. This is just a hunch, but I think in the near future the coolness of GNU/Linux will play a factor. It's like it's the environmentally friendly OS and with all of the polished distros like Ubuntu now available it really is a pleasure to use.