After much arguement and disagreement I contend the following:
1) Gnomes are tiny creatures about the size of a business card (on it's side of course). They cross-country ski, wear red pointy hats, and have rosy cheeks.
2) Dwarves are stout people, almost midget-sized but a little larger. They have irritable dispositions and like Alice Cooper.
3) Elves are tall. Lanky. Sometimes five or six hundred years old, with pointy ears. A short (full grown) elf is 5'8".
4) Trolls are human sized or larger, lumpy, and ugly. They are the bastard child of an elf and a dwarf with the personal hygiene habits of Alice Cooper. They're not only cranky and irritable, they're dumb too.
If I am wrong about this please let me know. These are things you don't want to get wrong, considering you'd look like a ninny if it came up in conversation at your next NRA fundraiser.