Colleen Lindsay of FinePrint Literary Management had a great post earlier this week on her responses to queries. She gave her reactions to 20 queries via Twitter and kindly posted a compilation on her blog. Here's the link. I will post two of my faves below, but you really must click the link and read more. It's quite helpful.
Query #16: This query was cc'd to multiple agents. Reject. You just shot yourself in the foot, dude.
Query #20: Loves me. Loves my blog. Has MFA. Won contest I've never heard of. Three paragraphs in and it's still not a query letter. Reject.
Also, since it's kind of related, check out Curtis Brown agent Nathan Bransford's post that lists stats of his 105-query three-day weekend.
Interesting fact from Nathan's post: "Queries that misspelled the word query or blog: 3"