yerba mate works well for me, good enough for Darwin, good enough for me! I'll probably use stevia as a sweetner on my trip though, sugar or honey being a pain to deal with and may attrack mean ol' bears

I also vote for tea, just easier to handle IMHO, lighter too. Not that I don't drink coffee, but I can wait till my mid-morning breakfast stop at a diner (hopefully) or convience store.