All my rods are medium/medium light, have one 6'10 cumulus thats rated medium heavy but its really a medium action rod.
I think a good medium fast action casting rod is one of the most versatile tools out there. With my 6'8 cumara, im comfortable throwing weightless plastics, jerkbaits, topwater, cranks, and spinnerbaits.
I rarely throw frogs anymore so i have no need for heavy action rods...
One of my all time favorite rods, and a great review. You can see how versatile it is...
http://tackletour.com/reviewshimanocumara68m.html