It's probably a little difficult running GIMP for photo editing. GIMP wants a half-dozen windows open at the same time to get much done.

Personally, I like having a few widgets on-screen all the time - a clock, a volume control - and I enjoy having two or three things open on-screen: a terminal and a browser, for instance, or two terminals ssh'ing to different machines. Having lots of display area helps. Pretty much every window manager can handle this, and it's just a matter of figuring out which one gets out of my way fastest.