[citation][nom]apache_lives[/nom]Vista and 7 are 99% the sameBEFORE you vote me down blindly -- you tell me what the real difference are besides vista's more aggressive caching and colour scheme.[/citation]
not just color scheme, but a hardware accelerated GUI, which off-loads a ton of crap from the CPU which is largely what capped entry level Vista machines.
But aside from that, most of the improvements in win7 are behind the scenes in finally implimenting a lot of what was learned fromt he minwin project. Mostly by figuring out how the OS worked, they were able to reduce duplicated code, and clean up the registry, while zipping up a lot of potential vulnerabilities. They also worked a lot on loading order to improve boot time.
To be honest win7 is really a big service pack for Vista, but due to the bad PR Vista had gotten, 7 needed a new name. But it was a bit more than just better caching and a paint job. It is a reduction of bloat, with better utilization of the hardware so that things run better, but no new features to speak of.
Win8 on the other hand takes the win7 core, and does nothing but add features. You look at everything from multi-screen support, to task manager, to IE10, to the superbar, to ram management and cannot help but notice (from a technical perspective), that win8 is a step forward. Not a huge leap of progress mind you, but it really looks like they took a hard look at their feature set, saw what people were installing to make win7 more usable, and then incorporated that in the OS design. Even with the new start screen, power users will quickly realize that all of the shortcut keyboard commands we have grown so accustomed to still work just fine. The GUI has changed, but the keys still produce the same results, which makes me quite happy about it. Again, not a revolutionary change that is worth $140, but an evolutionary change that is easily worth $40.