Last night at Philly GameWorks, we got a look at the Terrains feature in Unity. This allows you to sculpt worlds using the tools just within Unity. Using only built-in packs or free packs from the Asset Store, we created scenes and added first person style controls so that we could walk around our created worlds.
There’s more on the recap on Chris Gomez’s blog here: 3D Game Development: Sculpting Worlds With Unity