I've only recently discovered restaurant ware, and I'm far from an expert on it, but I could easily see starting a collection. One of the hallmarks of restaurant ware is it's sturdiness. These dishes were designed to stand up to the harsh conditions of commercial kitchens and dining rooms, and they have a nice, thick heft to them. Many pieces are inexpensive to collect and they come in a variety of patterns.
I love looking at all of the old logos of places that are long gone (and some that are still around) and wondering about the meals that were served on them and the diners who ate off of them.
Library Fashionista has a nice collection of logos:
As well as some interesting pink and white motifs:
For more inspiration, check out the Flickr Restaurant Ware group.
To learn more about restaurant ware, the Restaurant Ware Collectors Network is chock-full of information with active forums and a pattern ID guide.