** At the very least, include a link to [[Wikipedia:Administrators]] in the message telling people that they've been blocked, so that it will be easy for them to get in touch with me.
I've added this to the CVS version, as soon as Brion or someone else updates the code again, it's live.
As for blocking more intelligently, we definitely need this. Not blocking is not an option -- this may work on less active wikis where you just let the vandal work and then fix their changes when he gets tired, but there are actually people who want to use Wikipedia in the meantime.
The easiest way to stop vandalism, of course, would be to limit new members (automatically by requiring validated email addresses or manually by approving each member individually) and to require signing in to edit pages. I don't like that much either, but it would work.
Regards,
Erik