There's no percentage in rushing at this point. There's every reason not to. A buggy Vista release will only reinforce all of the "not going to install it until at least Service Pack 1" talk. Microsoft has too much riding on Vista and Office 2007 to release anything less than the very best build possible.
Read Robert's post. He makes an articulate argument and suggests a sound strategy. Microsoft has already set the stage for an announcement of an additional delay over the past few days by sticking to the new message: "We'll ship it when it's ready".
That's the right thing to say. Now it's time to put action behind the words.
Update: Even Scoble agrees. Although I have to agree with a comment to his post that says he's probably being overly optimistic when he says no one will remember that Vista shipped late (and feature light) a couple of years from now. Sure we will. Too many naysayers and disaffected users will "help" us remember.