Every homebuilder needs a good framing hammer. You'll use it more than any other tool. I have one of the traditional steel Estwing framing hammers. The vinyl grip is supposed to reduce shock, and it does to a degree. My hand still gets stiff after a long day of hammering. It's the 22 oz. model with a smooth face.
My contractor has one of the futuristic Estwing fiberglass framing hammers. The "weight forward" design does pack a punch, and the fiberglass handle seems to reduce shock more than my steel hammer. Marshall likes it but wishes it had a round head instead of square (the corners put dents in wood with every mis-stroke) and he thinks the nail-pulling claws aren't long enough.
Both of our Estwing framing hammers are built tough and should last just about forever. Good serious tools.