I'm running fully updated Snow Leopard, including the latest version to get ready for Lion.
The Runescape problem was something that started recently, (you can see a youtube video of someone crashing a Mac Pro just by trying to start the game.)
One of the Mac updates, I'm not sure which one, caused the crashing. As of the last update (was it this past weekend?) I was able to get on Runescape once, the second time, it gave me a dark screen and told me I had to hold down the power button to restart. After restarting I get a report that shows the Kernal Panic but it's not really helpful. I know I'm not the only one who's had this problem, Runescape recommends Firefox, but is also not compatible with Firefox 4!
I will do the Java Update tonight and see how things run.
The funny thing was that with my old 20" iMac 2.4 I never had a crash! This was the first thing that went wrong with my new i7. I'm not sure if there is a problem with the different architecture of the i7 compared to the Dual core, and Runescape, or it was the updates that automatically loaded when I first got my new iMac.
As a Side Issue, I'm not terribly happy with my 27" iMac compared to the old 20", the hard drive seems to be either noisier, or working more (Even though I upgraded to 8GB of RAM), Plus there is substantial Bleed-Through on the screen in the lower right hand corner!!