Hi Prof., I found your post while Googling and had to add my voice to the plea for help, since I have been having a very similar issue, and was looking desperately for references to it. However, I don't think it's unique to Lion.
Mid-2007 MacBook with 2GB RAM (upgrade from Crucial). Running Snow Leopard, but also suffered the same problem under Leopard. Beginning earlier this year, but with increasing frequency, my Mac has been kernel panicking on Flash videos. Performance often becomes a bit choppy in the minutes before the crash, and sometimes the sound cracks up beforehand, but it's also known to suddenly die out of the blue.
It's not an individual browser's problem - same crashes under Firefox, Chrome and Safari. I've tried uninstalling and reinstalling Flash, but to no avail. It's driving me nuts, and I too have been wondering whether it's just time to get a new machine. Can anybody shed any more light on this?