I once asked a Creative who had changed agencies what the brief was like at his new place. He replied: "Same shit, different boxes."

It's certainly true that every agency is obsessed with having their own unique format of brief... but it probably has far less impact on the work than their culture and clients do.
And yet... the document does communicate something about the values of the agency behind it.

Some briefs are aggressively unconstrained (see Fallon's brief, above). Others have the complexity of a psychology examination. 

And of course, they do influence an agency's output to some extent. They must do.

We are in the process of overhauling our creative brief here at Naked right now, and it feels like an exciting time.

What form of words can we come up with, that will have an inspirational effect on everyone in the agency, and produce work that blows juries' bollocks off?

I quite like this BBDO one.

Then again, I do slightly worry - about this one and especially the Fallon one - that although they look fantastic, and feel like they offer a lot of creative freedom, they could actually trip the Creatives up; for example by not including crucial info like the desired tone of voice, or any mandatories that are realistically going to have to be addressed. Maybe these follow on a separate page, I don't know.

So what do you like to see in a briefing document? Is there a good one you've worked to in the past? 

Do you like to see stuff like the business problem or brand purpose in there? Do you get upset if there's no proposition? Or is the format of the briefing document pretty much irrelevant to you... as long as there's some clarity and insight, it could be written in comic sans on a piece of bog roll, for all you care?