This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Firefox. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
It also doesn't say what level the malicious code runs at, can it get into the kernel/system? What's the damage level/threat? it has none of that and I'm assuming it is limited. Even more so in a 64bit environment, using a 32bit FF the exploit will be stuck in WOW. Not to mention that it requires you to visit a malicious site, which if you've been browsing long enough it isn't hard to spot. Get off those cheap pron sites.
IE9 also has ActiveX, one of the biggest security threats around. Not because it has shoddy coding but because of what it needs to do. It is the same with WebGL, you have to have certain privileges due to how Win operates. The FF exploit would probably be null on Linux, due to how userspace is handled. There have been many people over the years that say Windows poorly handles userspace and security. There is nothing you can do, UAC will never prevent those exploits because of the "trust" windows has for the users.
I'm on the 3.0rc2 right now, when Debian gets the 3.0rc3/rc4 I'll be on that. It isn't that I can't be touched, it is more or less nobody wants to run Linux exploits. I update regularly, to fix bugs and security exploits. It also doesn't matter what kernel you are on, as long as you are on a kernel that has the latest security patches. Debian Stable is proof of concept, it is one of the more well known server platforms.