Not sure if it's the best but I'm a huge fan of the Kaufman Stimulator on small streams. Anytime of year. Terrestrials work good in the summer. Of course matching the hatch on any stream works well.

I agree with buckhunter on carrying a couple of sizes Kaufman's. Egg and sucker spawn patterns and patterns like the grreen weenie are a good bet too for nymphing in most creeks.

I'm not sure where you live, matching hatches and times of year depends a lot on water and air temperature. Here in NW, Central PA, we just had big hatches of caddis, hendricksons, and grannoms. I've been doing well on caddis and stonefly nymphs too.

When in doubt, Google it. Go to smokeymountainflyguide.com They have a link to a hatch chart. It looks very similar to up here maybe a week or two ahead of us...It looks like cahills, march browns, sulfurs, and green drakes should be coming soon. I'm sure you can find some fishing reports online too that would give you some more specifics.

I have good luck by stopping in local fly shops. Look around, ask about fishing, buy a couple of flies (Even though I tye my own, I learn a lot from looking at other people's work), then run before they try to sell you something expensive (unless you need something expensive, then negotiate).