I like the cheap Columbia 29.99$ polertec fleece zip-up with zip-up pockets so useful for traveling, and hiking, stashing stuff in the pockets that zip With a t-Shirt under it I`m good in that down to the mid / low 30s. Add my gore-tex over the top and I`m ready for teens and 20s... colder and I want some long underwear. For the money it's great. I normally get 2-3 years before the fleece is almost melted to flatness... I've stopped drying it every time to help pro-long but at $30/each it's working great. I have some higher-end jacket/fleece stuff but I don't use it in the brush.