QsK, Linux is as different from Windows as Windows is as different from OSX. In other words, you'll have to relearn a lot of computer experience (like where settings are, how to get help, and how to find the solution on your own) as well as find new software. Photoshop and the rest of the Windows software you have will not run on Linux, unless you get software that pretends to be Windows, like VMWare or Wine.

VMWare, depending on your hardware, pretends to be running an entire computer, while Wine actually runs Windows software within Linux using compatibility layers. I do not recommend using any of these unless you absolutely need it.

And more often then not you don't need to. Linux has tons of software developed willingly by people like you around the world. Software like GIMP, Inkscape, Gaim, OpenOffice, and many others rival or better their Windows counterparts.

To sum it up, you are switching to an entirely new operating system. It's a new way of looking at your computer. A new operating system, no matter how easy they make it look, will have a learning curve you must defeat to successfully use Linux in the long-term. This is not unlike learning new software.