Like most of you, I grew up fishing regional patterns like the Bloody Butcher, House and Lot, Royal Coachman, and Renegade. Materials got better over the years, and patterns evolved. I like dry fly-fishing but tend to begin with a prospecting rig, usually a dropper rig that consists of a sizeable floater, usually a big Stimulator.
Attractor flies work great on the bouncy swift waters so typical of southwestern streams.
The trout don't have a long season, and they don't have long to make a decision about your fur-feather offering either.
You want something that will float, will hold up to repeated use and mostly, will catch trout.
So here's what my fly box for summer fishing in the Rockies looks like:
n Stimulators: This is my prospecting fly, my go-to fly, the fly I use more than any other in Southwestern waters. I like a few in each color: orange, yellow, green, royal and, surprisingly, black, all in size 12.
These will work early in the season to imitate stoneflies (golden, Salmon), as attractor flies and especially as the top fly in your dropper rig. Consider having a few in sizes 8,10, 14 and 16, too.
n Royal Wulff: You ain't a fly fisher if you don't have this pattern in your box. This pattern imitates most anything and is a super attractor fly, and the trout love it. Sizes 10-18.
n Ausable Wulff: Yes, this is a foreign pattern to the Southwest. That's one reason I like it so much. Created in the Northeast for their bubbly streams and timely mayfly hatches, this up-wing pattern floats well, is visible and imitates any number of Rocky Mountain mayfly hatches. It's especially good on long flats or runs. My favorite Mayfly pattern. Sizes 14-18.
n Goddard Caddis: I prefer this pattern to the ubiquitous Elk Hair Caddis because it works more consistently for me and the size 16 Stimulators work pretty much as an Elk Hair Caddis anyway. Sizes 12-16.
nDoc's Cork: Indestructible Stonefly pattern that works to imitate caddis as well. Rapidly becoming my top fly in my dropper rigs, especially on streams that have super stonefly action. Doc's Cork is also a fine attractor fly.
It's sturdy as all get out so you don't need but two or three in your box. Size 10.
n Green Trude or Red Quill Gordon: Your wildcard fly. Both are seldom-used, but the Green Trude is a nice change-up when nothing is working; the Red Quill is ideal for when those big, skinny mayflies dance over the water. Size: 12.
n Beadhead Crystal Woolly Bugger in black: One size fits all. Sometimes, when all else fails, and trout are just not hitting your other offerings, toss out this fly and strip-retrieve. You'll hammer 'em.
n Doc's Hopper T: Any hopper pattern will do, but this is my favorite. Come August and September, especially on meadow streams, you don't want to be without hoppers in your box. This one floats well, is easy to see and holds up to trout teeth. Sizes 6-8.
n Hare's Ear Beadhead: The most generic of all nymphs. The worker bee pattern. Get in sizes 12-18.
n Copper John Beadhead: Ten years ago, no one in the West used this killer fly. I catch more trout on a red Copper John Beadhead than all the other flies combined. Sizes 14-18.
n Pheasant Tail Beadhead: You could sub in a Prince Nymph beadhead or a Caddis pupa of some sort, but I have an affinity for this pattern.