In my experience, a cold tone paper developed in warm tone developer and then toned in thiocarbamide toner is perhaps the most flexible in terms of getting anything from subtle warmth to a real straight-on brown. Ilford MG IV or Zone VI brilliant both respond very well to thiocarbamide. A commercial version of this toner is the Fotospeed odorless variable sepia toner.

I second everyone's recommendation to get Tim Rudman's book on toning. It is complete to an exhausting degree.