Don't forget Steve Raymond and if you have not come across it yet check out Pale Morning Done by Jeff Hull - A novel but fantastic read. His 2nd book is out now but follows the standard short stories. It is a good read and I like his writing but I am finding the US writers are starting to follow the same path of having to have one story about bonefish, one about dogs and so on. If you are only going to read 1 of Geirach's books then pick up Trout Bum then if you want to read more go for Good Flies and Fishing Bamboo. Dave Ames' book A Good Life Wasted is worth a look as well.
Depnds what you want from the book as well. If you want more how to stuff them Brian Clarke's Pursuit of Stillwater Trout, River Trout Fishing by Peter Lapsley and Dry Fly Fishing by someone I can't remember right now! ON the entomology side of things there is Matching the Hatch by Peter O'Reilly (a good overview), Trout Flies of Britain and Europe by John Goddard (heavy going) and my favourite Caddisflies by Gary Lafontaine. For fly tying I would go with Gary LaFontaine's Trout Flies - Proven Patterns, AK's fly box by AK Best, 200 Popular flies by Tom Stewart and Essential Trout Flies by Dave Hughes.
I think that should keep you busy for a while.