After many years of not getting around to it, I decided that I absolutely had to go to Iceland. So I did. Four days and 1040km of driving later, I have come to the conclusion that Iceland is not actually part of Earth at all; it's a mislaid bit of some alien planet where the terraforming didn't quite take. It's quite the most surreal place I have ever been: there are mountains of black sand, lava fields covered in silver-green moss, places where the ground itself is boiling, jagged volcanic teeth everywhere... it is all just so incredibly unlikely. I can't believe it's less than three hours flight from the United Kingdom and that I hadn't been there earlier.
Incidentally, for reference, the absolute best online map of Iceland I've found is the National Land Survey. Satellite, infrared, proper detailed topographic, as well as gorgeous scanned historical map imagery. I just wish there was an Android version.
Also for reference: Icelandic uses two more letters than English. Thorn, lower case þ and upper case Þ, is usually pronounced like the th in thick. Eth, lower case ð and upper case Ð, is pronounced like the th in them.
(By the way, if you're driving from Reykyavik to Þingvellir, and this is pretty much obligatory if you're going to Iceland, don't take the standard tourist route of going up the coast and inland along route 36. Instead, go along route 431/435. It's a new and extremely good tarmac road, and the scenery is mind-blowing.)