Vulnerability researchers have the right weapon in their hands to push vendors on faster response times for security issues. I think that the best sample of how this should be done is David Litchfield. He does responsible disclosure, and uses gradually public advisories to push vendors (in his case, Oracle) to a more responsible attitude. HD Moore is being a bit selfish on this IE case, IMHO.
Instant disclosure brings too few benefits to victims (most cases don't have usable workarounds) and huge benefits to a very broad black hat community. I think that the fact that there could be people exploiting the undisclosed vulnerability doesn't mean the rest of the bad guys should also know it.
A mixed approach, with instant announcement of an open issue, without further details (only the product affected and the date when the vendor was informed) is the best option. Public disclosure can be used later if the vendor refuses to fix the hole.