Some websites make safari go crazy, and use 70% CPU! This causes everything else on this desktop to grind to a halt.
Is there a way to restrict safari to never go beyond a certain amount of CPU?
(btw - It's not just flash)
Enable the Debug Menu in Safari. One of the commands is Pause Web Process, another is Crash Web Process. Or the web process can be quit (or Force Quit) in Activity Monitor or any similar app.
And be sure to keep your Flash plugin current. Keep everything current/updated!