David Hyatt gives us Safari 1.2 release notes. The most useful tips:
In order to tab to popup menus, you need to go to your system preferences, select the Keyboard and Mouse panel, and then select the Keyboard tab. At the bottom of the tab is a checkbox next to the words "Turn on full keyboard access." Check that box to enable full keyboard access, and you'll find that you'll now be able to tab to popups all over the operating system (including Safari).
Another complaint I've seen on forums was that you couldn't type letters to have the popup jump directly to a selected item (e.g., typing "U" to jump to "United States"). Again, we obey the OS behavior, which does allow this, but only after you hit the spacebar when the control has the keyboard focus. Multi-letter typing is supported to complete to a specific item. Try it. You'll like it. :)
On a related note Firefox looks and feels very spiffy, at least on OS X. Too bad I've gotten too addicted to "bookmark syncing" between my desktop and the powerbook to switch browsers (I even subscribed to .Mac just for iSync between the computers, it's the only feature I use!)