I posted a comment on the blog about excessive CPU usage while testing the latest nightly. The site is one I developed for a church teen group. A good portion of the church uses macs and they have noticed the same issue with safari (I confirmed it). I told them if it bothers them to use Firefox until it's ironed out in Safari. Firefox2 and 3 seem to be affected by the site as well FF3 just not as bad.
Forgot to mention. Hardware is MBP 17 2.16ghz 2gb memory.
*** This bug has been marked as a duplicate of 19378 ***