Blue cheese - People wouldn't eat mouldy bread, so why is cheese acceptable?
Seafood - I can manage tuna and battered/breaded fish, but thats it. How people can eat anchovies is beyond me.
Those are the two I avoid at all costs, but other stuff I tend to stay away from is ...
Onions, Tomatoes (although I LOVE ketchup and soup lol), cabbage, liver, fruit cake, Chilli Con Carne, Peanuts, Tea, Coffee, pineapple, Curry (except Korma), Coleslaw, Muxhroom, Cheese N Onion crisps, seafood (deserves another mention, its vile), Supermarkets Sausage Rolls (only decent from bakeries), Cauliflower, pickles, turkish delight ...