I haven't been (lucky/bold/rich/stupid) enough to do a thru-hike, but I've come across some things that work for me for trips of one to 12 days.
First, I'll second the Just Tomatoes suggestion (http://www.justtomatoes.com/). I don't buy commercially dehydrated foods or meals, but I have found some of the Just Tomatoes berries and mixed vegetables locally, bought them, and found them to be excellent.
For food I'm mostly concerned with getting enough calories in a form that I can get down. If it keeps me going and tastes OK, it's good. I drink tea and bring candy for a flavor treat.
Generally speaking I concentrate on couscous, ramen, and instant mashed potatoes. Instant rice is good but isn't instant. Bulghur wheat would work, and I'll be trying it this year. It has the advantage that you can add cold water and let it soak for a while (an hour, or maybe overnight) and just eat it.
For hot meals I pre-package everything at home in ziplock bags, including seasoning. For most meals I add about four tablespoons of powdered milk, and another four of Parmesan cheese for the foods that it goes with.
Parmesan cheese is absolutely fantastic for me. Flavorful and salty. Contains protein. Keeps forever.
Mrs. Dash seasoning, garlic powder and onion powder work well, depending on the food, as would pepper. If it's a longer trip, like one to two weeks, I'll usually add two to four tablespoons of oil into the ziplock bag (works best with instant mashed potatoes).
Most of these foods can be eaten without utensils, especially the potatoes. When ready to eat, squeeze out the air, double check that you've sealed the bag tightly, then tear off one bottom corner with your teeth and squirt the contents into your mouth. I bring one largish ziplock bag for garbage and keep stuffing it with my empties, which I bring home.
The quart-sized freezer-weight bags work best. Light bags let oils migrate right through, and contaminate everything else. I found this out experimenting with bags of crushed potato chips for lunch. That was a great lunch (for me), but everything in my food bag got covered with oil that had gone right through the plastic. My hands too when I handled the bags. No really. It was horrible.
One favorite lunch when I don't mind the expense is crushed Doritos nacho tortilla chips. I crush them to reduce volume and make them easy to eat by being able to pour the contents right from the bag into my mouth (no oily or smelly hands). I get about three lunches for every two bags of chips, and it's salty and spicy. Quick too.
I have experimented with some home made brownies made with lots of milk powder, peanut butter, nuts, and oil, but wasn't able to dry it down enough. It was incredibly good but contained too much water and so it was much heavier than something couscuos.
I'm going to play some more with this.
I also have done a tiny bit of experimenting with shortbread. It's got carbohydrate, fat, and sugar, and you can add as much milk powder as you want. Simple but tasty. Some recipes use cheese as well. It seems like this might work if I can make it in thin sheets and dry it enough. Could serve for any meal of the day.
Hummus is something you might try. All you have to do is add water, mix, and eat. After a couple of days on this I started gagging and eventually threw it all away. Couldn't stand the lemony flavor, but maybe another flavor deserves another try. It has promise.
For longer trips I might try carrying oil separately, in a Platypus half liter bottle. I could add it to food just before cooking rather than worrying about oil leaking through pre-packaged food bags.
Final note: I'm the kind of person who can eat the same meals every day without a problem. As long as I get calories and kind of enjoy the taste, and have a little something else along as a treat (like peppermint patties or a bag of hard cinnamon or lemon candy) I'm OK.