Game coding

/frog/, I'm writing a 3D game and I need help with the logic.  I'm trying to model the ability to walk around anywhere on earth.  In order to do this (& keep it interesting), I need a map generator.  I have the temptation to model it after minecraft's block generator, but I don't want to have a blockly terrain.  It should be regular terrain, like Elder Scrolls or Halo.  Does anyone have an idea about how I would do this?

tl;dr: how do I make a normal map generator?

>>7
If you want cliffs, you can just square [or cube, or...] the results along randomly placed lines to increase the gradient.
You're obviously never going to get caves with a height map, so they'd have to appear somehow else.