And you are the authority on all things Vista? 8GB of ram wasn't needed, it worked great on 4. And even in 2007, 4GB of ram (while not quite commonplace yet) was not a major purchasing decision. Nor was a top of the line CPU needed either. Mid range units also ran it just fine. I had (and supported for others) plenty of these kinds of systems at the time and had little to no problems with performance.
XP being the best OS of all time I would also dispute... it will certainly go down as a great OS (I loved it too before Vista came out), but the best? It had some really serious security shortcomings when it arrived. Code isn't perfect of course, but Microsoft had really figured out how not to shoot themselves in the foot by the time 7 came out. Gone were the "lets include a checkbox as the extent of our firewall, but leave it off by default" - types of issues. Bugs and security issues that are discovered in Microsoft products these days are more about mistakes in the code, not mistakes in the decision making.