Just noticed a slightly different UI box when I clicked on the upper right hand X to close IE (with multiple tabs):

tabclosure

Previously IE7 and I believe IE8 Beta 1 just gave you the option to close all tabs.  To just close the one tab you meant to you have to exit this dialog and then select the individual tab.

One additional feature in this UI is the button to always close all tabs.

Anyone see anything else updated?