Self-healing capabilities, and the ability to do an 'in-place upgrade' (installing win over itself without data loss) were huge too. I had to wipe + reinstall XP dozens of times throughout the years, often for some small bullshit. I was a Vista beta tester, and got a copy for my machine as soon as it went gold. I went all-in and it was actually a fantastic OS. 7 was good too, but it didn't do that much new, comparatively. It stood on the shoulders of giants.