I'm currently building the PC for my custom build Xenophobe style cabinet
http://forum.arcadecontrols.com/index.php?topic=70282.0. My local computer store had a special this weekend on the ECS GeFORCE6100SM-M. (Picked up the MB for about $30 brand new). After installing my OS I used the CD to install the on-board graphics/sound/etc. The onboard nVidia graphics handles screen rotations.
I know when I built my first machine (a barcade for my mother for Christmas) I had issues getting the screen to work while rotated. I am wishing I had found this MB back then.
Anywho, thought you might all like to know.
Naloomi