People bug me enough about this coffee that I've linked to their web page, which has a full catalog, including the estates from which the coffee comes. You can order by calling 800-642-5282.
I have no commercial connection with these folks, beyond being a very happy client. I am particularly fond of their Don Giovanni house blend for espresso; I've never had anything like it (it is also one of the perks of being a graduate student on my research project). My friends are also very partial to their Blue Mountain and La Minita.
If you are a total coffee freak, and can afford to pay $300/lb for coffee, I might add that J. Martinez is also the only place I've ever found that sells Kopi Luwak (in 2 oz. lots). You have to ask about it; they only get it occasionally.
I never buy coffee at Starbucks, unless I'm at an airport and really tired and desperate; the quality was never better than "good," and has dropped precipitously to McCoffee over the last 4-5 years. For a chain, Peet's is my choice. There is one, for example, in harvard Square.
Olin Shivers / shivers at ccs dot neu dot edu