Whether it's a turnkey system, an off-the-shelf system, or a DIY system, doesn't really matter if it isn't maintained. If you've never done a complete teardown and rebuild of this system, after three years, I'd say that it's about time.
I agree with Colin. A complete reformat of your System drive might well be in order.
A complete reinstall after three years is extremely long. Often this is done on a yearly basis, some people even do it more often. You have no idea how much pollution you have acquired in all these years. Having done that, it may feel you have a new PC, without spending the money.
You have a very thorough method of slipstreaming your systems. Have you ever done a step-by-step article on your method. If not, maybe something to consider. It could be an adjunct to your excellent trio of artilces on hardware and software setup. Just a thought for your "free time."
This has actually crossed my mind, and I am investigating the issues for a good article.
However, Vista is quite different than XP, requiring vLite instead of NSIS.
Can't promise that I will succeed to write a good article, nor the time span when it will be ready, but it certainly has my attention.