I have read here and there that Firefox 3 crashes often (yes, Fernand, I am refering to you).
So I grew curious to see that mine had not yet experiment the first crash. I strongly suspected it was an Adobe Flash issue. And I have not installed that plugin, but instead the swfdec one.
You can read more about swfdec here: http://en.wikipedia.org/wiki/Swfdec
I noticed that I could do most of my regular "Flash needs", such as watching a YouTube video, or regular web-browsing without the annoying warning that one needs to download a plugin. Of course, I don't get to see most Flash banners, as I am extensely using AdBlock Plus, in order to avoid those annoyances... I happily use Opera without any Flash plugin, for a change, and mostly don't notice the difference.
One thing I noticed is my favorite podcast (http://www.europe1.fr/podcast/index.jsp) wouldn't play with sound with swfdec... So it is not "perfect".
It gave me the idea to uninstall Swfdec, and to install Gnash (http://en.wikipedia.org/wiki/Gnash) instead. Indeed, Gnash works fine in my Debian Testing PPC Mac iBook G3.
So I did get Gnash up and running on my Ubuntu 8.04 desktop. I fired up FF3, headed up too Youtube, and watched the video playing, but... no sound... Problem...
I thought, what the heck ? headed to Synaptic, uninstalled Gnash and went for the "Flash-nonfree", which is the proprietary Adobe Flash.
...Rebooted FF3... Headed to Youtube... Crash... Tried again... Crash...
...Went back to Synaptic, uninstalled "Flash-nonfree" and went back to Swfdec... It seems it is the "best" of the Flash player available right now for FF3, at least until further updates from Mozilla & Adobe...
I also makes me feel nice to use some Free Software when I can... Maybe I'll end up running Gnewsense ;) (just kidding..)
Anyway, I wish some readers can pass this info along when it comes to FF3 users complaining about random crashes... Use Swfdec, get rid of Adobe Flash !