I think the outcome of brewing depends on water temperature, leaf/water ratio, total volume of water, type of vessel, brewing style (which affects infusion time), and what tea it is. So shall we say the best temperature depends on the rest of the factors?
I guess my brewing style is similar to that of edkrueger's. I rarely measure things and therefore have poor idea about temperature and volume. I usually use newly boiled water. Yesterday I used a (not so accurate) thermometer) to measure the newly boiled water put in my thermos. It seemed 95C or 205F. Then I guess the water I use to brew tea is around 90-95C or 195-205F, close to the 195 end when I let the water pass by an empty porcelain jar (or yusamashi?
) first or throwing the leaves into the water instead of water on the leaves. I use 180-195F (I guess) for a few teas such as Bi Luo Chun, but higher temperature for most Chinese green teas in a small bowl or glass mug. But I have never really measured the accurate temperatures