Spammers are the bane of every email server administrator.  RBL's and blacklisting ISP's works.  But fundamentally there will always be other services and other ISP's.  A console window that could show a live view of any of the logs would be a great utility  (In UNIX:  tail -f {filename})  with a pause or page feature allowing you time to copy and paste an IP address into a WHOIS query.