I love Safari, it's the only browser I use on OS X. (Which is most of the time,) but those occasional times I'm on Windows, I actually do want to use a program that feels like a Windows program. iTunes feels like a Windows program. Safari (and QuickTime Player, for that matter,) do not. Not just the font rendering issue, but the interface elements as well.
I use Firefox on Windows, because it's a good browser, and its interface matches the rest of Windows. I don't use Firefox on OS X, because its interface *DOESN'T* match. (I used to use Camino, but switched to Safari when it came out.)
Can you imagine Steve Jobs parading the model on stage at MacWorld. His claim "Safari is fastest, safer and now definitely the sexiest way to surf the net...". I'm sold!