Great post over on Nathan Bransford's blog about novel word counts. How much is too much? What word count will take you out of the running from your first painfully polished query letter?
He says there may be a new trend toward shorter books because they leave more shelf space for retailers, thus making more money. He references this post from and editor on the subject.
So if you've crafted that pretty query with the dedication of a serial killer stalking his prey, don't waste it by proposing a 200,000 word manuscript - or a 40,000 word one.