10 things that make a good brief:

1. Clear content
2. Enjoyable/appropriate
3. Target audience defined
4. Specific outcomes
5. Appropriate tone of voice
6. Scope for development
7. Realistic ambitions
8. Clear deadlines
9. Defined context
10. Gives you the opportunity to learn

Most of these were decided as a class, I think possibly only the last one was my own addition. I think it also links with being enjoyable/appropriate. Basically in sum a good brief to me is something I can read and know exactly what it wants. The prospect of being faced with something so open that I can run free with it I find very daunting.