Pretty much anything goes, avoid dairy, rinse off fats and keep ingredients small.
Curries, chillis, stews, pasta, rice, sauces etc etc. I tend to do whole meals as though they're ready to eat and then dehydrate as one, I think if you keep the ingredients separate I think the results would be more appetising come rehydration time, mine usually end up as a mush but it all goes down the same hole as my mum used to say.
I use butchers lean minced beef or shredded chicken in 90% of my meals, I find they rehydrate better than actual cuts. Lamb works okay if you keep the chunks small. I prefer something bulky like a pasta or rice meal usually, chicken chasseur (sp) with rice, chilli and rice (I've had a hard time rehydrating kidney beans, they're like bullets even after 20mins in the cosy), beef with tomato based sauce, add chillies/peppers/onions to taste, penne/fettucine/spaghetti etc etc, add some bbq or Worcester sauce to liven it up a bit.
Diced or minced lamb, 1cm potato cubes, peas, carrots, spinach/cabbage, mint leaf, gravy powder, rehydrates into a baby food like mush but it one of my favourites, with a sachet of brown sauce sometimes. I've pulled out turkey curries from the freezer from two Christamas' a go, thawed them out and then dehydrated, went down very nicely with a fresh pitta bread.
A sachets of cup a soup make a nice addition to a lot of meals, cream of tomato in the pasta meals, oxtail in the gravy meals, chicken, mulligatawny, mushroom etc etc.
Cooked pasta and rice rehydrate quicker than cooking straight from the packet, saving you a bit of fuel.
Big chunks of mushroom take days to dry in a wet meal, avoid in stews or curries otherwise the rest almost turns to cinders before they're dried out.
I've eaten warm mush out of bags for years and the home stuff is on a par, I haven't really made anything much better but it works for me. It's when you try something like the Fuizion meals and realise there's a trick to it somewhere, their stuff is on another level but probably freeze dried in a fancy factory.
I'm lazy with my meals but there's a lot of scope for imagination, I'd like to try some Moroccan dishes with fruits and spices, better curries rather than just paste out of a jar, using a base tomato sauce and adding separate ingredients.
The Pour & Store bags work really well, they even wash out so they can be reused. £1 for 8 from Morrisons last time I looked.