1) As I was sipping coffee in the early hours one morning last week, I flipped through the latest Hakirah journal. I found in it several interesting articles, among them Ari Greenspan's The Halakhic History of Coffee, Tea, Sugar and Chocolate. It is a good summary and easy to read. - do so here
2) We mentioned the role that coffee played in Jewish history several months ago, regarding tikkun leil Shavuot. We mentioned Elliot Horowitz's truly excellent article Coffee, Coffeehouses and the Nocturnal Rituals of Early Modern Jewry - read it here. He wrote a brief synopsis of the article for Jewish Review of Books - read it here.
3) Several years ago, Robert Liberles wrote a great book that details the history in great (and entertaining) depth, entitled Jews Welcome Coffee: Tradition and Innovation in Early Modern Germany. Buy the book here (and read the introduction here).
4) There are still many halakhic issues related to coffee that can be discussed, but I realized that I have quoted two specific ones in the past year: a) R. Ovadia Yosef's analysis (in Yehaveh Da'at 4:42) of the potential problem of bishul aku"m and coffee, and b) R. Yisshak Yosef's brief analysis (in Rishon LeSion 1:43) of drinking coffee during pesukei de-zimrah.
5) Several years ago, R. Meir Mazouz spoke in the presence of R. Ovadia Yosef about his greatness as a Torah scholar. In the middle of the derashah, Hakham Ovadia pushed his cup of tea over to R. Mazouz as a show of respect to him. This fact was mentioned in the footnote to the printed derashah, in R. Mazouz's recently published MiGedolei Yisrael vol. 3 - read it here. Watch part of the video here: