Best new feature: Multiple tab closing behavior is more like Chrome's now - http://www.theinvisibl.com/2009/12/08/chrometabs/
(EDIT: Only when #tabs > 9 it seems. Otherwise all tabs have the "X".)
Unless you're on a flash page, because flash captures your keyboard, because flash hates you.
However there is a bug, clicking the X sometimes causes the need to click it twice because the first time it is ignored.
I havent seen this on linux yet, is it still ugly as all hell or did they improve it like they did with windows version?
Edit: Try it yourself if you disagree.
My guess is that there are more people accidentally closing extra tabs than people who want to close a lot of tabs they haven't seen in a while.