James Maliszewski on Grognardia posted a question yesterday: What image sums up D&D for you? Telecanter had this image posted on his blog, and I am in complete agreement with him. I, too, spent a lot of time looking at the PHB when I was young, and I was always drawn to this image. It may have been for the reasons Telecanter cites, but I think it reminded me of The Hobbit, with Bilbo and the Dwarves descending to find Smaug's treasure. Maybe Thorin's fathers had placed a magic mouth in the secret tunnel to guide anyone going that way.
I also notice that this image has influenced me more than I thought, because nearly all of my dungeon drawings seem to resemble this image in terms of lighting and architecture. Weird how something like that sinks into the back of your brain and just stays there.