Terrain algorithims

I don't think terrain methods and their advantages can be enumerated or described here as well as they are at VTerrain.org. That's probably all the reference you need to get answers to your question!

Thanks! I had seen that page a while ago but couldn't find it anymore because I couldn't remember the name. :)

I can also pimp a very recent thread about terrain rendering: http://www.gamedev.net/community/forums/topic.asp?topic_id=457195.