Expect this to kick up another can of worms...
A relatively clean new look, it primarily focusess on four pieces of functionality: 'Filters' to help better sort the activities of your friends, the famous 'Stream' which can be customised to show only the data you wish and 'Publisher', a rather Twitter-ish redesign of the status update which is spiced up to enable easy sharing of links, photos, videos and charity events. There is also the subtle rephrasing: 'What's on your mind?' replacing 'What are you doing at the moment?' to indicate its wider abilities. Lastly, 'Highlights' is a fancy way of saying more and larger targeted ads but that's hardly surprisingly during these financially shafted times of ours.
Personally I think it looks perfectly fine - perhaps a tad sober compared to the calamitous yet somehow more endearing earlier designs. It also seems to shove applications even further into the background. Yes, we were all sick of being attacked by zombies and vampires (and notified all the darn time) but that whole aspect to the site looks to be dying a death. Whether that's a good or a bad thing on the other hand, I'm not so sure.
All I do know is there's likely to be yet another overblown protest like the one which followed the 2008 Facebook profiles redesign. In fact I'm sure there are already a vast number of Facebook groups protesting it vociferously right now.
Expect the new version to be applied incrementally across all 175 million profiles as we speak...