...a long time ago, back when I wrote, instead of read queries, I used to think editors were this huge amoeba-like thing that lurked off in editor-land and waited to pounce on unsuspecting writers if they didn't format their queries right.
The yahoogroups I belonged to, and the forums, and writing things all said stuff like, "make sure there's a hook" "start with part of the story. Editors love it when you launch into the story...." There was the snazzy-opening camp, and the start with a question-camp, and the if you have a comma in the wrong place, they're going to track you down and kill you-camp.
I still belong to some of those groups. They still talk about commas, and great hooks--but writing is subjective. Not every editor is going to like every query. The hooks go by in a blur--sometimes they even hurt, going off on weird tangents that don't come anywhere close to the actual story. I don't grammar check queries (I know it's horrible of me, but what can I say?), and I skip over bits that doesn't relate to the submission.
I like a straightforward--this is why I picked this house. This is the target-line, word count. This is my story--insert short description. This is my contact info. This is my (carefully polished, but not totally OCD) synopsis.
Professional as possible--no IM text or inappropriate slang. Like Nicola said--treat it like a business. We're all in it together.