If we're talking dragons here, they should be guarding something really important. I'm trying to think of a story in which a dragon was sitting on "just" a pile of dough, and that was it.
EG: in the Hobbit, the treasure was secondary to the fact that Smaug had taken over the dwarves ancestral home.
Other dragons (eg: Fafnir) might be more of an environmental issue, again, the treasure begin secondary to the fact that the dragon's poisoning the local ecologies.
That being said, you should give your monsters treasure appropriate to your setting and story. Some GMs like to give out lots of treasure, some don't. When all else fails, talk to your players, and see what sort of game they want. Maybe there's a certain artifact they want to get their hands on? Maybe they're into a gritty game where every bronze piece counts. Maybe they want to become feudal lords, and clearing out a minster-infested castle is just their first step in their long range plans.
Please note I do not actually work for Chaosium; I just do the occasional freelance editing work for them.