I have yet to see this mentioned around the Mac web, but along with session saving, draggable tabs, very sexy inline find, resizable text fields, some enhanced privacy options and bookmark/history searching, the Safari 3 beta for OS X (and likely Windows as well) presents a long overdo fix for a very annoying rendering bug:

In Safari 3, DHTML content displayed over Flash content no longer disappears or displays erratically!

Thanks, Apple. Now fix that memory usage, and get me Flash on the iPhone. Pretty please?