If these don't inspire you, then nothing will :)
http://www.flickr.com/photos/clik2/with/8534882784 (http://www.flickr.com/photos/clik2/with/8534882784)
Agree with your comment and thanks for sharing
Some amazing moments of some beautiful places. Don't love all the images, but some of them are really spectacular.
I would like to see some of the moisture that is in some of those images, brought into terragen. Maybe there is more of it than I can think of right now, but most terragen renders seem to be of mostly dry(ish) places.
The images I liked the most in that collection in the OP, had lots of water in the air. Seems kinda hard to do like that in TG. Difficult for me to get right so far anyway.