I definitely second getting a slow cooker OP. Using it overnight is a great idea or on days when you are home to put extra meals into the freezer for the week ahead.

Other stuff we do:
* spaghetti or pasta with tinned salmon, pesto, garlic, olive oil and parmesan.
* One pot meals - there's a couple of chicken/rice ones we like, you get the packets in the section with the slow cooker ones. One is chicken and leek with veggies and the other is a mild Indian chicken curry with spinach. Neither take more than 30-40 mins to get onto the table.
* homemade pizza - as long as you've got all the ingredients in the fridge/freezer they only take about 15-20mins in the oven.
* packet gnocci - it keeps forever, you can put any kind of flavour sauce with it and DS totally loves it!
* If all else fails and we are running really late or have nothing organised, I always have tinned soup in the pantry. There are some nice flavours around and it takes less than 5 mins!!