After looking at pages (like Red Bull) that have encouraged their fans to do scavenger hunts of their Timeline, I didn't noticed too many "Likes" on old posts or historical milestones. Doesn't mean people aren't at least passively viewing the content, but I'd agree - News Feed still seems like top dog.
Facebook Milestones are new feature of the Timeline design being rolled out to all pages on March 30. Be sure to spend some time on your "Founding Milestone" and experiment with "Pin to Top" to see whether anyone is browsing your Timeline. Seems to me that the News Feed still rules. :)