Okay Apple, why are you doing this?
The close button on the windows Safari 4 are on the opposite side of the tab than the Mac OSX Safari 4 version. The idea behind is probably platform UI consistency (windows has the "X" in the top right corner, OSX in the top left), but it is annoying as hell when you are using both platforms.
Okay cmd-W/ctrl-W is the keyboard way (which I use mostly), but this is confusing for mouse use.