Ahh, the old days! I learned a bunch of OpenGL off NeHe. I even won one of the demo competitions. :)

Another great one for general graphics/demo/simulation coding was "The good-looking textured light-sourced bouncy fun smart and stretchy page" (https://web.archive.org/web/20031218105827/http://freespace....)

And for landscapes in general, Ken Musgrave did some awesome work although I'm having trouble digging up the more technical stuff he used to post.

And then there was software like Terragen and Bryce could produce some great rendered landscapes. It's getting me all nostalgic. :)