I look forward to again finding my favorite apple varieties, grades of maple syrup other than A, locally made cheddar, bialys and pastrami when I daytrip to Manhattan, and lobster and clams when I hit the coast.
There are three foods that have been pleasant surprises in Denver which I will miss: Chiles from Hatch, New Mexico which are roasted locally at farmers' markets and roadside stands, peaches from Palisade, Colorado on the western slope, and the sweetest cantaloupes I've ever had (and they're cheap!), from Rocky Ford in southeast Colorado.
Denver is a great restaurant town. While you can enjoy superb upscale dining, the best part for me has been the plethora of middle eastern restaurants (and markets).
I leave never having fulfilled the desire to make my own tamales. Maybe I'll stop by the Mexican grocery and buy some husks and masa harina on the way out of town to take back east.