When it comes to thermal underwear, it's all wool for me. Modern wool underwear is really comfortable while still having good insulating properties when wet or damp. And trust me, your clothes will get damp if you wear them long enough, particular if you have to put on a water/windproof outer layer. One (thin) layer of wool undergarments and one outer layer (windproof and breathing, or wind+waterproof as situation dictates) is appropriate for most activities for a huge range of temperatures, basically anything from +10C / 50F and downwards... Middle layer is only used when I'm standing still.

Fleece has lots of merits, though. Lightweight, comfortable and dries quickly. I use it for middle layer if and when that is appropriate. Like so many else here I also enjoy having a fleece jacket lying around to put on whenever I feel like it.


I second the opinion that you can get a lot of functionality for reasonable sums if you have the wits to shop around at a discount. There is one area where I won't compromise and that is my outer jacket. I live in a climate that makes spending the money for a high tech jacket with functional hood, ventilation zippers and so on is well worth it.