Here are a few samples of Jamie Keenan's work. Jamie does some very inspiring work, check out Keenan's site. I love the Otherwise Pandemonium cover, it's great to take (or see) something and create an unexpected image out of it. I had been talking with Keenan, and below is his response to his own creative process, though he says that he has no true process.
"...but I do have a bit of an obsession with tying the image and the type together in some way. It's really easy to end up with a bit of type slapped on to a nice picture (especially when you're a freelancer and lack the resources of a design department which can commission a photographer to come up with something) so I'm always trying to think up ways of getting the two elements to fit together, as in the bits of my work you picked out. Other than that, I've also got a thing about diagrams, maps, charts, emergency exit instructions etc... and using existing forms of design like signs and logos that people are already familiar with and subverting them in some way. Oh, and optical illusions. Book covers are quite small so it's good if you can get each element to do more than one job - does that make sense? I think I've got a thing about circles too.
Other than that, I always feel it's good to read as much of each book you're working on as you can stand and leave it to roll around in your brain for a week or so - I'm sure that some ideas get formed that way without you knowing it's even happening."