HTTP_X_FORWARDED_FOR'216.104.15.nnn'
HTTP_USER_AGENT'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)'
HTTP_ACCEPT_LANGUAGE'en-us'
The last one is new, since today.
It was caught following a user around and causing havoc in a restricted area. The whole range now banned at the firewall.
Edit: I forgot to mention, also seen from 150.70.84.nn - both are using HTTP/1.0 and wasting a huge load of bandwidth.