I live in Santee (East County San Diego)......These are my top picks for you. Mexican food/ taco shops are what San Diego is all about. Here are some options for you below. Basically, if I ever moved away from San Diego, these are the places I would miss and crave.
Mexican/Taco Shop- Lolitas http://lolitasmexicanfood.com/
I would recommend the California Burrito (Carne asada, french fries, sour cream) or the Carne Asada Chips (Basically nachos.....carne asada, shredded cheese- not melted though....weird but works, guacamole and sour cream). Lolitas is the best tasting taco shop in SD by far IMO. Here is another place El Pollo Grill http://www.elpollogrill.com/
. Best pollo asado burrito in San Diego. Great chips too
Fish Tacos- http://www.tjoysterbar.com/english/ourmenu.htm
. Best fish tacos in San Diego IMO. Best part...only $1.00! They are a little small and you can eat 5 at a time but for a buck they cannot be beat. My order usually consists of a shrimp ceviche tostada and 3-4 fish tacos. Under $10.00 and absolutely delicious. Its a real small place though and does get crowded so its best to get there right when they open.
Egg Rolls- http://www.yelp.com/biz/a-chau-san-diego
. They make these little Vietnamese egg rolls. They have 2 types...ones with a traditional wrapper and one made with rice paper. I prefer the rice paper...crispier and crunchier. They fill them with a pork filling, carrots and some rice noodles. They are addictive as can be. Cheap too... 45 cents each. Great snack.
Royal Mandarin- http://royalmandarinrestaurant.com/index.html
. This is where buffetbuster mentioned (National City) The regular food is just ok...the reason to come here is the Salt and Pepper wings. Deep fried chicken wings coated with msg, salt/pepper and green onions. These things are like crack. They are incredibly delicious and always super crunchy. You get get an order of about 12 for $8.00 or so. We ALWAYS get these for parties or pot lucks at work. Haven't met a single person who does not like them.
Fast food burgers- If you haven't had one already, definitely head to In N Out for a double double http://www.in-n-out.com/
. If you are in North County San Diego there is a place called Farmer Boys http://www.farmerboys.com/
. They have "The Farmers Burger" which is double patties, cheese, bacon and avocado. Its one of the best fast food burgers I have ever had.
San Diego pizza sucks....if you are coming from NY, dont even bother trying any pizza out here ;-).
Thats all I can really think of that I personally would crave and miss if I ever moved. If you can, definitely try Lolitas. I could eat there every single day and never get sick of it.