The biggest switch is that photos are being used wherever possible. And your vitals, like place of birth and job, are now pulled out, naked for all to see.
Links to your interest, favorites, friends, etc, will be replaced with images in the new profile. And if you've been tagged in a photo recently, it'll show up near the top, too. (Luckily, you can opt-out of showing the one your mom posted of those 'awkard teen years.')
Navigation has changed, in that the tabs you're used to seeing across the top-right are now directly under your profile pic -- which is not larger by half.
The Info tab has more functionality, too. There are new categories for you to choose favorites in, like Philosophy or Athletes, for instance. And the Friends tab is way different, with a visually celebratory grid of your (supposedly) favorite people.
Facebook has added more than a little functionality here, things like ranking how your friends' pics display below your profile. The overhaul is very visual. And it's all very customizable.
Hand-in-hand with new customization? That's more data about you. More for advertisers to mine. Behavioral and semantic searching will go from firehose to full-on hydrant with all this new data.
It was inevitbale, of course, but FB has -- with its massive user-base and scale -- has tipped us forward. Again.