upgraded to 3.3 over the weekend (love the new drag and drop media loader, by the way! :-), and the only thing I have encountered, is that the Admin pages for my Dashboard, and Comments section, the background is all black, and not white.
Going through all the other Admin sections (Posts, Media, Links, etc.,), the backgrounds are still displaying white.
This isn't really a big issue, as I can still see enough to do what the sections serve, as the text color is not all black itself, so am able to still read, and the body background fields are still their white selves... but is just an odd thing. And it is cross-browser, at least with the ones I have - Safari, Firefox, Chrome.
PS: I thought I could embed two screenshot images showing what i was describing, but they didn't work