I'm with aprilgem on this one. But one of the new features in SC2 I really like and use allot is the Warp Function which, combined with the other edit>transform features allows you to change the perspective of an object you paste in, warp it to the correct proportions, then seamlessly blend the article so that no one can tell you've inserted something that was not there.

The number one reason for Photoshop though is portability.

Back when I used PSP, I sent off an image I did for t-shirt transfers. The shops that I sent the file off to kept asking for it in Photoshop format. I finally found one who could convert the PSP file, but now that I use Photoshop, I never have to worry about such things.

Printers like to use layers by color when silk screening (if you've ever done it by hand you'd really understand this better).

Photoshop is the industry standard, if you plan to do any serious work for commercial purposes, its Photoshop.Say for instance you want to make a texture map for Poser: Poser will allow allot of different image files to be used in textures, including Photoshop, which, makes better renders because the process is lossless, it makes for better renders.

Yank My Doodle, It's a Dandy!