At present I use a Montbell windshirt with a hood that weighs about 3.4 oz in the XL size. I like a loose fit and Montbell is a Japanese company so the sizes tend to run a bit small for Americans, even when they make sizing adjustments for us. More often I wear a Large.

I don't recall the name of the model and it wouldn't do you any good to know it, as they've replaced it with a different model since I purchased mine. I fully agree with the sentiment that such a windshirt is amazingly good at keeping one warm in moderately chilly and windy conditions and it's one of my favorite pieces of gear/clothes. It even works a treat to keep the mosquitos from biting through it!

As I recall it was in the neighborhood of $75.