In reply to KieranD:
For DofE and CCF trips (the only time I've used genuine boil-in-the-bag rations), we had military ration packs from cadets - can you get these from Army Surplus stores? Strip out quite a few things, though, since they are heavy and very calorific so you don't need them all (e.g. I've never eaten the cooked breakfast, the pate, half the biscuits, half the drinks...).
Since then, I tend to go for the following:
Breakfast - water porridge - but I'll make it woth good quality giant oats and carry a few raisins to make it tastier! Problem with this is the pan (leave it to soak while you pack up the tents, washing up liquid in a (now very venerable) film canister). For more luxury, use milk (planning your routes through the odd village makes life so much easier)!
Lunch - stuffed pitta breads, salami, tracker bars, chocolate, dried apricots or similar...
Dinner - Quick-cook Cous-cous or rice that I've added chorizo, peppers, tomato puree etc to. If I've got milk, then custard and cake, else just cake (homemade chocolate-dipped flapjack is a personal favourite).
For day walks I'm really lazy and just carry a pork pie/sausage roll/scotch egg or similar, a chunk of malt loaf, a few chocolate bars and an apple. I'll get the rest of my 5-a-day for breakfast or dinner!