We eat vegetarian meals every other day due to trying to keep costs down. My OH is a farmer so he is very active, he's also a physically big chap and is always hungry! I find that the following meals work well at filling him up, they're healthy and he enjoys them, which, coming from someone who would eat meat for every meal if I gave him the chance, is high praise!
Stuffed mushrooms - Big mushrooms with a herby, cheesy topping (bread crumbs, red onion - saute for 5 min first to soften -, parsley, feta/cheddar/ricotta/whatever cheese takes your fancy/is in the bottom of the fridge, and an egg to bind together. The proportions can be varied to your taste. Pop it the food processor, spoon on top of the mushrooms and bake for about 15-20 mins. I usually serve these with homemade potato wedges. The filling works equally well in stuffed peppers or you can use it to make a vegetarian 'sausage roll' with puff pastry (v nice cold for lunch boxes too).
Fajitas - I omit the chicken and either use twice the amount of peppers and onions or I use Quorn chicken style pieces sometimes, or kidney beans.
Stirfry - use Quorn or tofu instead of chicken, just make sure you have a tast sauce/marinade to cook it in.
Oven roasted vegetables and halloumi - any veg that takes your fancy eg. peppers, red onions, cougettes, mushrooms, whole garlic cloves, aubergine etc and halloumi - chop, place in a roasting tin and drizzle with olive oil and paprika/rosemary/whatever herb takes your fancy and roast for about 45min. I serve these with potato wedges again, or a green salad, or couscous mixed with some harissa paste.
Broccoli/cauliflower cheese bake - I just make a white sauce and sprinkle a little cheese on top rather than making a cheese sauce to keep it a little healthier.
Spanish style omelette - fry diced chorizo, leftover sliced potato, any peppers or mushrooms you have together. Whisk your eggs together in a jug with a splash of milk and seasoning, pour over the mix in the frying pan and cook until set. Good for using up leftovers.
Roast vegetables mixed into pasta with whatever pasta sauce takes your fancy, crumble some feta over the top, or mozzeralla and bake for 10 mins.
Slowly fry red onions, mushrooms and quorn, mix a good dollop of cream cheese in, stir through pasta (reserving a few tablespoons of the pasta cooking water to 'loosen' the sauce). I've also tried this dish with fresh peas stirred in near the end, or with spinach, or broad beans.
There's lots of different things you can do, part of it is getting out of the mindset of having to have 'meat' in every dish. If you view it as an ingredient, ie. like you would view pasta say, you wouldn't feel that you have to include that in every meal before it become a 'proper' meal.
As long as most meals have a mixture of carbs, protein and vegetables you should all be fine.
Vegetarian protein = ), milk, yoghurt, eggs, nuts, quinoa, beans - kidney beans, chickpeas, butterbeans, black beans, baked beans, lima beans, canelini (sp?)beans, red lentils, split pea lentils, green lentils, cheese - ricotta, mozzeralla, halloumi, feta, cream cheese, herby cheese eg boursin, cheddar cheese, Quorn, soya, tofu, pinenuts. There's plenty of options once you start to look at it.
Part of it is just getting into the habit of looking at ingredients a little differently in that you haven't got a 'big' flavour (in the sense of beef/sausages etc) to work from.