Well every one is pretty right on about the nine footers virtues but you might want to also consider an eight and a half foot. You talk of fishing the sierra's and there are a lot of nice streams around those lakes. For the distances you cast a dry fly a good tip action rod in 8 1/2 or 9 foot should work great for you. I prefer a 5 wght. but wind, large flies and fish might indicate a 6 wgt. Go to the fly shop and cast, cast, cast. Go in with no preconcieved notions and you might be surprized what suits you. Good Luck

Mike