I also eat a couple of apples every day - Fuji and Honeycrisp are my favorites.
A new favorite dish is to take one of those "Just for One" broccoli & cheese sauce singles from Green Giant and stir in a couple of ounces of tuna or chicken - YUM.
Fage NF yogurt. One of the things that I had to give up was regular cheese, to much fat and salt. Now I make my own yogurt cheese, no fat, no salt, easy and tastes just like cream cheese! I usually mix herbs or maybe sundried tomatos or kalmata olives for a spread on veggies or sprouted grain bread. YUM!
*Veggies and fruits (esp the mixed frozen for quick and cheap)
*Canned low sodium soups and broths (I add the veggies to it, or use the broth instead of butter for sautes).
*Sauted onions cooked in broth or simply alone in a non stick pan. (actually, they don't stick to any pan I have). They somehow make any dish seem more fattening than it is.
*fat free and low cal ranch dressing. Not quite the same as the regular, but after awhile you forget what the regular tastes like. I hardly use margerine anymore for things like sandwiches, etc. I just put some dressing on the bread.
*Montreal steak spice. I put this on my green salads instead of dressing, or added to the dressing. I put it on my potatoes instead of butter, etc.
*Krafts fat free cheese slices (chedder is only 35 calories!)
*Tacos. The ones I use are only 75 cals each, or two for 150. I stuff them full of grilled veggies, chopped tomato, and spices. I even add the cheese slice to them if I have enough calories left.
When I use lots of ice in the diet pop, for some reason it tricks my taste buds into thinking I am drinking regular sweetened cola. Sometimes I even have to check that I didn't pour from the wrong bottle!
And water .... instead of juice, I add about 1/5 of a water bottle with OJ or Lemon juice, etc. Then, I fill the rest up with water. It flavours the water without too many calories. And now, they even have that new flavoured water which is great and zero calories.
It's not really a "diet" food, but I can live on frozen chicken tenders. All you have to do is get a couple out of the bag and throw them right in a pan. Fast, pretty cheap, portion controlled and tasty. I also use a lot of lemon juice and couscous. In fact, if you mix all of those together with a bag of frozen broccoli and a little low sodium soy sauce, it makes a great meal.
I know it's not very exciting but lettuce is my best friend.
I'm gonna second this.
Lettuce and onions. I eat tons of onions. I eat onions every day. And like Blue said, I can make a whole meal out of a big huge salad by tossing on lots of low cal yummies. In fact I had a big salad just yesterday for lunch and tossed on grape tomatoes, shredded carrot, onions, fresh mushrooms, diced chicken breast, sliced avocado, green pepper and a small sprinkling of fat-free croutons (gotta have my crunch). That was my meal. Plus I put lettuce in my pita sandwhiches. I've ALWAYS got lettuce and onions around. If I go low on onions or notice my lettuce starting to turn brown, I panic! Gotta get to the store for more lettuce and onions!
I usually mix herbs or maybe sundried tomatos or kalmata olives for a spread on veggies or sprouted grain bread. YUM! 
