I have found that the quicktime plugin crashes the browser as well but see no sign of a "plugin container" thingy. Any idea where it is on a mac?

Not sure about MAC, but plugin container is a seperate process that starts up when firefox does as well, so when addons crash, firefox doesn't crash. Not sure if you have task manager on MACs.

On a Mac, open your Activity Monitor (search: Activity Monitor in Spotlight-upper right in menu). This will show where all of your memory is being used. You can force quit specific plug-ins from running there.... I have the same issue and my Mac's fan with start to churn and get louder and louder unless I quit the flash plug-in. I will be reverting back to 5.whatever and turn off auto updates until fix is implemented.

I have exactly the same problem. The plugin container hogs cpu resources (70%!) making firefox extremely sluggish and unresponsive. Once the process is terminated through task manager everything runs smoothly with a warning at the top that flash has crashed. I'm running all latest software on win7 64 bit. Would be great if anyone had a solution for this. Not sure if it's a problem with flash or firefox but it does start getting on my nerves either way.

when I used Firefox 6, it was incredibly fast but when I download mp3 or other media files, the download doesn't contain the file name. the name of any file downloaded is "videoplayback". Plus Java doesn't work at all. So please send us the solutions since Firefox really is the best browser and I adore it very much.

Might want to read my post in the following thread:

https://support.mozilla.com/en-US/questions/882024?s=firefox+7+crashes+&r=18&as=s