Here's a bit I missed: Tiger's Safari has a new feature called "private browsing." Simply launch Safari, then click Safari-> Private Browsing, and you will be met with the following dialog:
Supposedly, it's for security when browsing in public areas.
My take: Browsing without any history or tracks of your browsing? Porn mode.
Good thing Tiger also has parental controls, otherwise, I could see this being abused by every hormonal teenager on the planet.
Update 2007: Welcome diggrs. Check out our current coverage of Safari and the announcements from Apple's WWDC07.