I don't know why you wouldn't know who Derek Riggs is, but in any case if you don't he was Iron Maidens original artist. I ordered a Derek Riggs original print (11x17), what a delight to deal with him. My print was delivered, signed by the artist. One of my favorite albums, Iron Maidens PowerSlave.
I ordered Print #7 for my office. I'm not sure what makes Powerslave so great for me. I'm sure its the music as well as the time in my life that I was exposed to it. I know some of It is definitely Derek's great artwork that attracted me to the music as well.
Here is a good interview with Derek about what he does.