I've been using WXP for 12 years now, and just like Charlton Heston, they're going to have to take my old PCs from my cold, dead hands!
However, with that being said, back in early February I bought a new OptiPlex system from Dell with Windows 7. I already had it on my laptop and it's a stable, reliable operating system. I am also a tax preparer and I can't even envision preparing tax returns or spreadsheets with a touch screen. I know, W8 SP1 can now accomodate FPs.
My new system was less than $1,000, out-the-door, and so far, it's working just fine. I don't know what browser you're using, but WXP will only go up to IE8. My W7 system has IE 11. I've noticed that I am not able to fully load websites with my WXP system (GA, GB, GI, Bud's, etc). No problems at all with that new W7 machine. Most websites are now oriented towards W7-W8/IE 11 which has become the new I/T standard. I don't do Chrome or Macs, so I can't comment there.
I also "bit the bullet" (figuratively) and replaced the old laser printer as there are no W7 drivers for it. I upgraded (replaced) my eight year old router at the same time.
Buy a new system with all of the software pre-loaded at the factory. If you're an old duck like me, get a larger monitor screen so that you won't need to squint and you can see those skyrocketing GB prices more clearly. You'll also have a much better processor, video card, etc Just like paying the big bucks for a Model 29-2 (with a 6 1/2" barrel, of course) over time as you really begin to enjoy it, you'll forget how much it sandbagged your gun budget!!