Yeah my Macbook Air 2012 freezes despite uninstalling and not using Chrome anymore.
I am getting freeze with Firefox 13.0.1 (even after turning off the graphic acceleration - which was a suggested solution) - usually happens while watching YouTube.
I took my Mac to the Genius bar and managed to replicate a freeze on Firefox. (was a software update that triggered that freeze).
Suggested action:
1) Verify and Repair disk - done
2) Create a new user and use that one instead (could be corruption with my user set up) - next step
3) re-install the OS (OR take the MacBook Air to Apple for a full scale diagnostic - note the MacBook Air got the standard diagnostic at the Genius bar and got ticks for everything except battery and power - because it was not plugged into a main at the time)
The guy at the Genius Bar was very helpful and also asked why I preferred Firefox to Safari - my answer - because of the extensions and options. (Yeah this is probably also why Safari might be more stable than Firefox

)
I used to a old Macbook that used Lion OS X and did not freeze - maybe the issue is related to Integrated Graphics? (However in fairness there are more differences between my Macbook and my Macbook Air than the graphics card.)
So while a culprit may have been identified. It looks like there are others.
UPDATE: Kernel Panics still happening. Going to the Genius Bar.
