Hi all. What technique should I use to generate a big terrain? What would be the fastest - best looking way of doing it? Would like to have hills etc.. Thanks,

I liked the approach simcity3k took:

Make a 256 monochrome bit map whatever you favorite size is (1024x1024?)
Use a spray can & some effects from you favorite paint program, blend a once or twice and save
Make a bmp->terrain loader that reads in the bmp file and scales & translates it to your terrain dimensions & format