To a large extent, it depends on the water I'm fishing. A 12 inch fish in a small stream that normally only produces 6 to 10 inchers is just as satisfying as a 25 inch fish on streams that are known for their 25 inch fish. As for the rods I use, I let the fish I expect to catch dictate the rod to use. I recently read of a 28 inch plus brook trout taken on a 3 weight and it took over half an hour to land the fish; the fish was then released and the angler felt great because he was practicing C&R. In all probability that fish didn't survive.