The new Flash 8 beta breaks Flickr, but does improve performance considerably on Nikeid, and other heavy flash sites. Flickr uses flash for its slideshows, which v.8 will not show at all.

The beta does not improve performance to the extent that I was expecting from the earlier Macromedia demos. Also, since Apple insists on having Safari continue to loop flash ads, movies, and sites while a Safari window is minimized or hidden, flash still bogs down the OS much more than on Windows IMHO.