On an unrelated note, yesterday I downloaded the Earth map, where 1 block is equal to 1 nautical mile, to try it out and it was 3.5GB when uncompressed. The biomes are a little screwy due to ice forming, which means that a large swathe of the North Atlantic is now an ice-sheet.
(Image rotated to put north at the top.)
I set out to cross the Atlantic last night and it took me 9 minutes to reach Newfoundland.
Then the game started lagging like crazy, so I had to stop.
3.5GB?? Wow, that's huge. The problem with the current map system is that it's just too low res for it to be close to useful. I made a map and then was wandering around town with it trying to map it and I couldn't recognize anything on the map unless it was huge like Robert's arena. I like the mechanics of the system though. I think it's brilliant. But unfortunately I don't think the low res is something a zoom feature would fix. It makes me wonder why Notch bothered to make a map feature if it was going to be like that. Now, if we could take the maps and put them up on our walls as unique wall hangings, that'd be cool.
I'm also disappointed that maps don't work in caves, which honestly is probably the place where people would find it useful the most.