Are you looking for mid-layer while hiking or once you have stopped? My experience is that when I am hiking a heavy weight base or a featherweight base + light weight fleece (like the Patagonia R1) and shell keeps me quite comfortable at 20F. My daughter likes using a featherweight base + lined wind jacket like the Marmot DriClime Windshirt in those conditions.

For when stopped, something puffy is really nice. The best value IMHO are the down jackets from Montbell but they aren't cheap. REI has made a Primaloft Jacket with zip off arms which I often see on the clearance rack in my local store.

--Mark

PS: Starting next Thursday Patagonia beings their annual Memorial Weekend sale. If you have an outlet near you it the outlet price - 40%. They also typically have pretty good sales on their website.