Actually we are talking about the operating system, and not the company... I have installed Windows 7 since last June (replacing my older XP which I used for the past 4 years). It actually performs better.
Fighting the good fight meant using Mac OS or Linux? How did you arrive at that conclusion?
A Mac OS X is good, but it is only restricted to one type of hardware, the Macintosh. Which is why the Market share is low, there are lot of Personal Computers out there that can use the other Operating Systems.
As for Linux, it's good as a server or for doing specialized computations, but not really for home use. I think most of the desktop linux users are developers or programmers, who spend most of the time compiling the Kernel or tinkering for optimization. You cant ask my mom to run a sudo command from the terminal you know, or ask my 14 year old niece to install a program from the command line.
I think for the home users, Windows XP will continue to persist, unless newer programs will start not to support it.