This is a project that I started a few weeks ago, forgot about, and then came back to. It is by far my largest terrain to date, which is probably why I got bored of it for a while. Anyway, on to the details!
This terrain originally had 1 valley, surrounded by about 4 mountains. I kinda lost interest then, and quit working on it for a while because I wasn't sure what else to add. A few weeks later, I came back to it thinking that it needed a large lake. With an island. 5 or 6 mountains later I had pretty much what you see here now, minus a bunch of landscaping. ;) This terrain has a total of about 9 or 10 tall mountains, a bunch of ridges, multiple waterfalls, streams, caves, and valleys. All biomes should be correct, and if you want a surprise go to a mountain top while it's raining.. ;) The mountains themselves should have a bunch of iron/coal ore in them, if I did everything right. Everything below sea level will have ores spawning like normal.
Tools used: Voxelsniper, Worldedit, Bioman (for the biomes), SPC.
Texturepack: Modified Dokucraft Light.
The download link leads to a folder, you can pick whether you want the map in creative or survival mode, it's got an option for each.