I don't know how or why, but on Windows Vista, I lose the functionality of the 'escape' key (in all programs other than Photoshop) when I have Photoshop CS3 open.

The workaround: use "shift + escape" instead of just the 'esc' key in other applications when you have Photoshop open.

Hope this saves some poor Windows/PS user a bit of frustration... it certainly has made things just a bit less aggravating for me!