Adobe issued an emergency Flash update for actively exploited vulnerabilities on OS X and Windows. Apple has blocked vulnerable versions of Flash for OS X and won't let you use Flash until you updated to the version at the time of this writing, 11.5.502.149.
I installed that update tonight, and at least for me, it's obvious the patch was rushed and needed more time in the oven.
For the first time in many versions, Flash crashed.
I saw John Gruber's post on the emergency Flash patch the other day too and remembered he linked to his November 2010 post about going Flash-Free. He says it's been working out pretty well for him in the 2+ years since.
So that's it, I'm done with Flash on the home iMac. If I didn't have the whole Creative Suite installed at work, I'd dump Flash there to.