Chalk me up as one of those affected.
Running OpenSuSE Factory, KDE 4.7. Rendering in KDE is okay. This seems to happen in Firefox and Seamonkey on my system.
Mine has artifacting whenever a pop-up menu or tooltips appear on screen. Oddly, so far this seems to only affect Seamonkey and Firefox for me.
Never had this problem with the previous driver. Unfortunately I can't go back because both Debian Sid and OpenSuSE Factory has moved on to Kernel 3.0.0.
Oddly enough the corruption only happens on the OpenSuSE box, which is running on a pair of GTX260s SLIed. On the Debian box which sports a lone 8400GS and runs Gnome 2.30, no artifacting is observed.
Okay, this is odd. I decided to try out a copy of Seamonkey from the Mozilla website and it doesn't have this glitch either. So it may have been something wrong with one of the graphical libraries that is used with the OpenSuSE-provided version of Seamonkey.