Fort Collins is home to one of the finest fly shops in the country, St. Peter's Fly Shop. When I first moved to Colorado, I remember going to the Old Town location and being treated like a long time customer and friend from day one. The folks that work there are always happy to share advice, and have a knack for displaying that fly fishing item that you suddenly realize that you have to buy.
The Old Town location is housed in a historic building that gives true character to the shop. A while back, St. Peter's opened a south Fort Collins location in a storefront after taking over another fly shop.
Just recently, they announced that they had moved into another building at 2008 E. Harmony Rd. I visited the new digs for the first time the other day, and was amazed at the location. They have restored an old house/barn, and turned it into a beautiful fly shop that has to be seen in person to be appreciated. Visiting both locations gives you a sense of Fort Collins history, which blends nicely into the history and tradition of this sport that we love.
Check them out at http://www.stpetes.com/