As posted above, APX100 was the best. I have enough for several years stashed away. Maybe by then AGFA will have divested itself of the film production wing and someone will pick up the slack with 'new' 4x5 APX100.
In the meantime, I have seen nice stuff with FP4 and Efke100. For 400 film It's hard to beat Tri-X. I don't shoot 400 at all so my fastest film in 4x5 is Classic200 shot at E.I. 160.
tim in san jose