Anything by Gierach is great. I keep a copy of Death, Taxes, and Leaky Waders next to the throne in the master bath. Its a compilation of stories from Trout Bum, Even Brook Trout Get the Blues, Standing in a River Waving a Stick, and others. Each story is worthy of being read several times, and they are just short enough that I can usually get up before my legs fall asleep.
As a kid in Montana, we had an old copy of Norman MacClean's A River Runs Though It And Other Stories on the shelf next to the fire place. I loved the title story, of course, but the other that sticks out in my memory is Logging, Pimping, and My Pal Jim. It's not about flyfishing, but it is the kind of story most flyfisherman like to read. It's got mountains, woods, rough characters, and a sense of humor.
Life is hard. But it's a lot harder if you're stupid.