Actually, just looking at the evidence below, I did sample quite a lot of the food...
Yonah Shimmel Knish bakery on East Houston Street
I had a mushroom knish on my first visit - I had to return to get a blueberry cheese knish on my last day (very tasty but I couldn't finish it, 'twas huge and very filling)
Moishe's Bake Shop on 3rd Avenue in the East Village, spotted when I arrived by cab from JFK, in a jet lagged haze, mighty relieved to have found it as the baked goods were very fine
Blimpie - home of the sub sandwich (presumably a reference to the shape of sandwich, rather than the size you will be if you eat a lot of these)
Russ & Daughters, East Houston Street, for delicious smoked fish