I was on a hat kick recently, probably triggered by this project:
Pattern: Brambles Beret
Yarn: Manos del Uruguay Rittenhouse Merino
Needles: US 4 (ribbing), US 6 (body)
I knit the Medium size and probably only used just over half of the skein of yarn. The unblocked hat comes out really, really small. Even after blocking around the usual dinner plate that I use for blocking tams/berets, the hat is still small and quite close fitting. I would definitely knit a Large size next time.
It's a pretty pattern and works up quickly.