Just noticed this issue. It's with Skyrim updated version 1.6.89.0.

With EVGA GTX 580 - Nvidia driver version 301.42.
This happens with FXAA, supersampling, transparency AA, and so on... all turned off and on through Nvidia control panel and through Skyrim.ini and SkyrimPrefs.ini

http://www.youtube.com/watch?v=gLOLDibg-2M&feature=plcp

Any help or suggestions on solving this issue is appreciated. Thanks in advance!