K2 seems like a really interesting theme for WordPress. It is still in beta at the moment, but I have installed on World of Dave just to see how it works and looks. I actually really like the feel of the Contempt theme I have in place on here, so it will take something special for me to move away from it.
One thing I need to add to Contempt is an edit link on each post – having to go through the Admin panel each time I want to correct a typo is a pain in the neck.