I would highly recommend Brianne Haagenson with Captivated Events. She is amazing - check out her site:
You can find samples of engagement photos under "couples". She is very affordable :)
Raymond Fermin is great and does wonderful work. His style is more casual and less posed. Great guys also!
You can find his site by searching google for Raymond Fermin photography. He has a Facebook page also :)
Sites are endless but red rocks is a great spot for something more unique, boulder has a lot of amazing places for pictures also.
Click on each tool to see a sample.