Matcha - High in caffeine because you ingest the entire leaf
I'd like to share with you this informative post on About.com: Factors influencing caffeine levels in tea. Thanks to Lindsey, my friend and tea professional, for summarizing a tricky topic.
In the past few years, more thorough and sensitive testing has shown that the old idea of pouring off the first brew of your tea to decaffeinate it doesn't work like we once thought. It has to do with caffeine's "desire" to be in a state of equilibrium. The caffeine keeps on giving, so to speak, in addition to a host of other factors, like tea varietal, growing method, maturity when picked, processing style, brewing technique and even water temperature. If you and I brew the same tea side by side, chances are each cup would differ in caffeine levels. Yours might brew a bit longer, I might use cooler water, etc.
I've been learning more about this over the past few years, and I think Lindsey has done an excellent job of summarizing the findings.
* Photo from Microsoft images