an .htaccess ban is the most effective, banning ip's through doesn't work very well.
I have 16K members, I keep finding him because of his IP, he has a distinctive IP address so banning his IP would get rid of him....at least for a while.
you can ban ip under the vb options. it is under user banning options. The only problem is that he may have his IP address changed. I know comcast in my area has changed my ip once.
Banning the ip works well for the less bright of people - I changed the message on our forum so it doesn't actually say your ip is banned - I've always thought it a bit silly to give these idiots a BIG clue as to how you banned them.
Perhaps you can install the miserable users hack but change it so it works off that specific ip rather than a usergroup. That will confuse the hell out of him and limit him.
Bringing up an old topic, but a hack that would like like the IP ban in the CP but instead blocks the ip from registering again (maybe by just giving a plain old 404 error page upon that ip trying to register again) would be cool...
Why not just ban the IP you ask?
Well, I would like the banned user to still see the board and see the psots in reply to whatever it was that made him get banned...