Before people jump in to comment, let me clarify:
(1) I don't think it is Main Street looking south from Passaic because the large 3-story building on the SE corner of Main & Passaic Street is much older (built mid-late 1800's), and it's not in the subject photo
(2) I don't think it is Main Street looking north from Passaic Street because the editor has other photos on file of that stretch. It's smaller homes, close together, and close to the street
So I think it must actually be Passaic Street looking west from Main Street, even though the postcard doesn't say that. In fact, the street is very straight for many blocks, which Main Street isn't. Any other ideas out there ?