About 20 years ago when I was at Uni, I lived opposite a LIDL (back when you had to find a carboard box to carry your stuff around!). They used to do a Ristorante Frutti Di Mare frozen pizza (I think it was 2 in a box) and it still pisses me off that it was discontinued. It wasn't just prawns, it had mussels and other stuff (possibly olives) on it. I still think about the bastard things today and I just thought there must be others who have their long lost foods.
Others for me are Brannigans crisps and more recently, Fries To Go! Oh how I could demolish some Fries To Go right now!
What are yours? Join in my rant :)