The rules for knowledge checks state:
Answering a question within your field of study has a DC of 10 (for really easy questions), 15 (for basic questions), or 20 to 30 (for really tough questions).
In many cases, you can use this skill to identify monsters and their special powers or vulnerabilities. In general, the DC of such a check equals 10 + the monster’s HD. A successful check allows you to remember a bit of useful information about that monster.
For every 5 points by which your check result exceeds the DC, you recall another piece of useful information.
But how much information is revealed on the initial successful check? All vulnerabilities? Just the creatures environment, name and type? Just the answer to one question such as "What is the creatures HD"?
I am curious if there is a compiled listing of what gets revealed, I know the monster manual IV lists what info is revealed based on a knowledge check for a monster but the rest of the monster manuals are not so generous.