I've built three now out of western red cedar. One is dark brown with streaks in the grain that are nearly black, one is blonde with a little pinkish "blush" on one end and the latest one (a storm paddle that I finished shaping last night) looks like it's going to be orange. All of them are under 30 ounces, even with a lot of wood in them. Cedar is light, naturally rot resistant, has very nice flex characteristics (it flexes quite a bit before breaking) and you never know exactly what color it is until you finish it.

I find it very easy to work with (I'm a hack woodworker at best), though it is soft and prone to damage if you bang it around, which is almost inevitable when dealing with 6'-8' stick in a small work area. Fortunately for me, dents in cedar steam out pretty easily.

Cedar does seem to vary a lot in density. The brown stick is coarse grained, very light and soft. The blonde stick is heavier, but still quite soft. The orange stick is tighter grained and heavier still, and was much harder to sand than the others. The differences in weight could be readily felt when picking the stock, but the color of the brown and orange sticks was nearly identical when in the raw 2x4 state. If the color matters to you, you'll have to wet the wood to determine it.

The advantages of one-piece sticks are simplicity, low cost and speed of construction. I started the storm paddle two days ago and had it cut, shaped and sanded in ~8 hours of work time. If I had laminated the blank, it would have probably taken me another 2 hours of work and at least one night's drying time. Aesthetically, a one-piece paddle looks more traditional, if that matters to you. As for cost, cedar paddle blanks cost me $15-$17.50.

The advantages of laminated blanks are aesthetics and optimization of materials. If you use different woods, you can optimize the characteristics of each one for a particular section of the paddle. For example, you might want a spruce loom for strength, cedar blades for lightness and ash tips and edges for durability. The downside is increase complexity and time of construction, increased cost, and increased weight in the finished product. It's possible to build a lightweight paddle from a laminated blank - Kent LeBoutillier has made a 27 ounce laminated paddle - but most I've seen are in the 40+ ounce range.

However you decide to do it, you'll end up with a paddle that is uniquely yours and have fun making it.