When I run Portal and Episode 2 full screen, the display is offset down and to the left, clipping a large part of it off. The amount of offset seems dependent on the screen resolution. Windowed works fine, but full screen would be preferred ...
This is from the Orange Box downloaded from Steam. Portal, Episode 2, and Team Fortress 2 all play well. (I have not tried HL2 or Lost Coast from Orange Box to see if they also have the full screen problem; in the past I played Lost Coast and Episode 1 full screen without the offset.)
(This is on a MBP 2.2GHz MacOS X 10.4.)
(I'm also having trouble seeing the text in the options panels, but I'll try the tip in the other thread.)