Photoshop yes. (6.1 - tomorrow I get new CS2 version)
Mostly I play with contrast and brightness, unsharp mask is also a good tool. very little use with curves.
In my opinion, AH screenshots are quite good without any editing, contrast is the most important thing I think.
My monitors native resolution is 1280x1024 and I resize all screenshots to 1000x800.
Images in that testgallery are sized to 640 x (something)