Brighter in photoshop then elsewhere

The image below looks brighter when I open it in photoshop vs elsewhere (windows pic viewer, IE, firefox). I had a friend try it on his machine and he said they looked the same. It is pretty noticeable with this image on my machine. I figured I might have the color settings wrong or the proof setup but I checked it against his and they are the same. I have tried playing around with the proof setup and setting it to monitor rgb and proof colours on makes it very close to but still slightly brigther then others, when my friend sets his to monitor rgb it is darker then vs others.

Check the bottom post in this thread:
http://forum.teamphotoshop.com/showthread.php?t=25516

thanks!