The SPAM in these forums has gotten way out of hand, and I agree, IP bans are a good start. Yes, cormac, people can get around IP bans, but SPAMMERS don't take that kind of time, they just SPAM a forum and leave. When they come back to SPAM again, if they can't get in, they just move on to the next forum.
People that want to start flame wars will work around an IP ban, but that's because they are obcessed with continuing their war. SPAMMERS just find new forums to spread their disease in.
I despise SPAM, and those who spread it. ;(