I use an 'American Harvest Snackmaster' (= Ezidri) but there are plenty of dehydators available - have a look at http://www.lakeland.co.uk/14210/My-Kitchen-Food-Dehydrator

My favourite dishes are:

1) Beef hash (Corned beef hash but using decent minced beef) - use Smash rather than try to dehydrate potatoes

2) Bolognese-type sauces

3) Curries

4) Anything that you've made too much of at home - just make sure that you break it down into small pieces to aid the dehydration / rehydration processes.

5) Stewed rhubarb. To die for!

When I bag the individual meals I add some appropriate flavourings to the bag to compensate for any of the flavours that are driven-off by the dehydration process. This can be a pinch of dried herbs, a quarter of an oxo cube, a pinch of curry powder etc.

As has already been mentioned, potato doesn't work - so use Smash. Chicken doesn't work - although I've has some success with tinned chicken.

There's no doubt about it, dehydrating your own food is far better than buying commercial stuff. Apart from anything else, you control exactly what goes in and you control the portion size. A dehydrator will pay for itself in a short time, I wouldn't be without mine now.