I love the idea of crock pots, and we have a few meals we make with them, but I do not use mine often. It is partly going to depend on your schedules and food preferences. I like casseroles with a common base, either egg noodles, rice, or macaroni. You cook up the main part, mix everything, and bake it for a half an hour or so until hot. Sometimes just having everything handy is as easy as spending a little more time putting it away after shopping. I have also lowered our standards--we do not have seven hot, full meals each week. Sometimes dinner is everything scrambled in with eggs (take a few minutes to rinse some spinach, toss in some cheese, cut up a tomato, then scramble it all). We also have had sandwiches for dinner or other typical lunch or breakfast meals that are simple and quick, saving the "big" meals for weekends.
We buy ground beef in bulk (95% lean) and I freeze it in bags, some shaped already for burgers (I like the big burgers and we load them up), some frozen flat in a serving size for a casserole, etc. It is easy to thaw what we need (my husband works evenings and sometimes come home and really wants a burger--so much faster to thaw and it is already formed). I separate chicken breasts in meal portions and freeze. I am getting better at putting a meal's worth of leftovers right into the freezer.
Some of my favorite casserole dishes include Hot Chicken Salad (from my MIL). It is rice-based with cream soups, curry, hard boiled egg, almonds, etc. LOVE it! Great for leftovers! I also make a macaroni casserole by mixing elbow macaroni (cooked) with tomato soup, sour cream, lots of shredded cheddar, some kind of vegetable (green beans, steamed brocoli, etc.), and browned beef (you can mix in Worcestershire sauce, minced garlic, some onion, etc. with the beef). Bake it in a casserole dish--easy and yummy family meal.
Planning a menu is a great idea. We don't like to strictly commit one night to a meal, so we will come up with five or six meals we want each week and plan to make them and then see what we feel like sometimes. My husband works several nights a week so I'm alone with the boys and we usually eat leftovers those nights. Unfortunately, I have had many dinners of popcorn after work while the kids had PB&J. :)
You could also bump your meal time back a tiny bit and make a right after work snack time--I am usually starving right after and had to try not to eat junk for dinner. I also sometimes mix something up the night before that I just have to bake for dinner, so I would have no excuse.
Leftovers are also great for bringing to work--I hate making a separate lunch but never mind heating up something from earlier in the week. It is a good way to save something if it is not enough for a family meal.