Totally agree. The best role she's ever had outside of Buffy. I don't even think of the kiss scene, but rather the scenes where she bates Sebastian (two in particular - 'Down boy' and 'You can put it anywhere')
I also have a thing for Famke Janssen (sp?) in Goldeneye as Xenia Onatopp, and (I know it's predictable and cheesy) but Megan Fox as Mikaela Banes in Transformers (both 1 and 2). Her entire role in the films may have consisted of little more than 'Rub the camera with your crotch/chest' but damn! That girl is hot!
Plus Angelina in Mr and Mrs Smith (especially the Tango scene).
(KA27's laptop proceeRAB to short out due to the large amount of drool that has just fallen on it)