Dandy Mall has a great Carrefour and theres a shop called Gourmet Egypt which has great food too. Mall of Arabia has a great Spinneys. Personally I dont really like either for anything other than food....but then I am not really a very good shopper.
i am sure that there are smaller markets around there too like ragab and metro. carrefour is best for foreign treats (and meat and veggies) but you'll find better prices at the smaller markets for basics.