In the rush to tout the severity of the bug, it appears that the tech media generally have done a poor job of explaining the issues.
First, it's not a flaw in Safari; it's a flaw in the handling of SSL by multiple Apple apps, including Mail. Changing browsers removes the vulnerability only when browsing, but an unpatched system is still vulnerable through these other apps.
Second, with respect to OS X, only systems running Mavericks—10.9.1 or 10.9.2—are affected. You folks on Snow Leopard, Lion or Mountain Lion are unaffected, and the 10.9.2 update patches the problem for Mavericks users.
Third, the vulnerability, as Ira points out, is limited to shared networks. That's a big deal with mobile devices, but not quite as wide an exposure for those of us using Macs on private networks in our homes.
