Contributions to Philosophy: From Enowning. The fairly controversial 1999 translation of the Beitrage zur Philosophie: vom Ereignis by Parvis Emad and Kenneth Maly for Indiana University Press. This text is for diehard Heidegger readers. It is not something I would recommend to anyone who has not been reading Heidegger for some time and who does not have a great deal of background in the translation of Heidegger.
Heidegger's Contributions to Philosophy: An Introduction. A nice overview and introduction both to Heidegger's original text, Beitrage zur Philosophie: vom Eriegnis as well as the fairly controversial translation by Parvis Emad and Kenneth Maly.
A Heidegger Dictionary by Michael Inwood. Really one of THE BEST overarching resources for understanding what Heidegger means by a given term and where the term appears/changes in Heidegger's work.
Husserl, Heidegger and the Space of Meaning: Paths toward a Transcendental Phenomenology by Steven G. Crowell. I believe that Prof. Crowell is one of the best thinkers in the United States today. There are some really key insights in this text, and anything you can find by this gentleman, a student of the great Maurice Natanson, you find them and read them.