It all nearly disappeared. For the past couple of days the map would crash whenever I tried to load it because it had gotten so big through mods and I was so far from spawn. I have MCEdit on my computer so I loaded that up and moved the location where my character would spawn on start back to the house. Then I looked on Minutor and noticed something strange about the area. A chunk of forest land north of my spawn had disappeared, leaving an empty square of ungenerated land. That patch of land had instead moved into the water just east of home base. The chunk adjacent to it to the south was missing, although when I opened the save it became water.
But the map was sloooowwww! None of the other saves were having this problem. Running MCEdit and Minutor at the same time on the world seemed to have a negative effect. Thus I decided I would restore it. Fortunately I had made a backup so I opened the restoration program and began restoring. With such a large world, it takes a few minutes. Once it completed, I go into Minecraft and find that the restored map isn't on the list of saves. I go to where the saves are located and see that World5 is there. Inside it... an empty folder called "t". The backup had gone horribly wrong somehow.
Still, I don't give up just yet. I try to restore it again, since the backup file is still on my hard drive. I was going to write a blog entry about how I've lost the Minecraft World, but I held off. This time the restore went smoothly and now, it's back to normal! Everything is where it should be. The map lost about 5 megabytes but that's of little consequence. It even undid a chunk error that popped up a few days ago. Under my base is a fairly extensive strip mine. I had a new branch stemming off of the first one, and a wacky error replaced the connecting tunnel with a new chunk which had coal and iron in it. I never got to it though, because this restore put the tunnel back in place.
Hopefully, the map still looks about the same as it did before. I may have lost the outskirts but I can regenerate those at a future point in time. I should stay put though, until I've begun developing plans for what the nations will look like.