By contrast, the Firefox 3 beta 4 I'm presently using scores a lowly 68/100 (FF2 does even worse), and I have to admit that I'd like to see it higher. I have no idea how the various IE versions perform, but it's probably be safe to assume the worst and be pleasantly surprised if low expectations are exceeded.
Achieving a perfect 100/100 score means more than just standards-compliance, which is massively important. It also means that the WebKit project developers meaningfully CARE about standards-compliance and are dedicated to achieving it. The only way they got this perfect score was to focus on resolving (tested-for) defects until there were none left, and they have worked hard to get this positive outcome. It is somethng all of us who work in the web medium should congratulate. Perhaps there's hope that one day we won't have to design around browser incompatibilities and foibles. How much nicer it would be to know with confidence that our designs will render consistently and operate as intended on all major browsers!
So, congratulations WebKit, and Opera too! Well done!!
PS - How does your browser do? See for yourself, run the test page...