I would have to say probably an Admantite golem. I had only one weapon that could hit him and it was the Staff of Rynn (imagine that...a STAFF!!) so it did about 1 hp of damage each hit and that hit wasnt very often, while he kicked my ass with about 25 hp of damage. Firkraag was as easy as pie, Thax took a while longer, and the Black Dragon died in about 5 secs. Liches are nasty but they're fun. And finally, beholders suck when your at low level (stupid friggin flesh to stone stuff)
------------------