With 4x5 grain is really a non-issue with enlargements up 16x20 with any speed film. My older ektar lenses seem to have a sweet spot at about f16, so unless I am doing portraiture and want a larger aperature Ilford hp5 is the most flexible for me.
The choice of devloper also should be considered. HC110, XTOL and PMK have been my choices for LF, but my recent tests show Pyrocat-HD to produce the best negatives at a full ei of 400. YMMV.