Mandelbaum's translation somehow manages to be respectable poetry while being quite literal and accurately reflecting the meaning of the original Italian. This is a rare feat. The notes for the beautifully produced Everyman edition are new and quite adequate.
This book does NOT include the Italian text. The Bantam paperbacks of the Mandelbaum translation do, but with skimpier notes.
The other important edition of the Comedy is by Robert and Jean Hollander. Their translation is very accurate, but not distinguished as poetry. Their notes, however, are extensive and excellent - a real education in Medieval life and thought.