Always on the lookout for cheap and useful paddling clothes, I picked up one of these lightweight pullovers from the clearance rack at an Eddie Bauer store. Discovered it was the most functional shirt I'd ever used for warm weather kayaking and bought two more from their Outlet website (only $20 each in both women's and men's sizes as I write this review -- they don't stock them in the stores at the moment).
The fabric is supposedly some "special mineral based" polyester (whatever that means) but it does work at keeping you really dry on a hot damp day. Design is excellent: streamlined but not tight fit, long in the body, raglan sleeves with flat seams that don't chafe, front half zip has soft thin nylon zipper for venting with a neat little hood at the top so the slider doesn't scratch you under the chin. Collar is tall so you can zip it to keep rain and sun off your neck. Fabric is allegedly SPF50 -- I do have trouble with sun poisoning on the tops of my forearms with long exposure but this shirt seems to protect as well as sunscreen, I admit. Best part of the design is fine gauge mesh panels along the sides and all the way down the back, the places that suffer the most under a PFD -- my skin stays dry there when I wear these shirts (in fact, they are the only shirts I wear paddling anymore.) They machine or hand wash like a breeze and dry in the dryer in 10 minutes, or overnight thrown over a towel rack. They pack tiny for travel. A folded up one fits in a quart baggie.
Besides the half-zips I bought they have regular tees and pants in the line and even a sleek hoodie that might be handy for warm weather rolling practice to keep long hair out of your eyes, if you don't mind the flower child graphic on the lower back.