I love a V-neck shaped cowl. It doesn't fit too tight around the neck, and it keeps me warm no matter what kind of neckline my shirt has. This one is lightweight so it can be worn when the weather gets a little warmer as well.
The stitch pattern is a series of simple yo's and k2togs...or SSK's depending on which way they slant. The cowl is knitted back and forth and then the cast-on edge is seamed to the side. Picot borders finish it off.
It's surprisingly fast, and takes just over half a skein of this yarn, so it's also affordable.