I bought a really light paddle a few years back. I can't remember details about it though. I do remember a few years ago, while on a week long camping/kayaking trip in Cape Breton, my arms were pooping out a bit. Someone gave me a paddle that was just a bit lighter, but that made all the difference.
I'm not really thinking of speed because I want to go a lot faster. It's more about paddling longer distances with a bit less effort. I paddled almost 21 miles a couple of years ago, and at the end of the day, I couldn't even push myself up out of my boat (Hurricane Tampico 140L). I may go longer down the road, but I'm not certain yet.