When I'm not fishing dries, this is my favorite fly, hands down. Nymphing the Poudre, I've found that you can't go wrong with this one. I like to tie in some red wire for the ribbing. No particular reason, other than that it seems to be really productive.
Hook: Size 18
Bead: Tier's choice
Hackle: Brown saddle
Abdomen/thorax: Peacock hearl
Rib: Tier's choice (I like red, traditional gold)
Wings and tail: Goose biots (tier's choice)