In response to Newdayrising's reply:
I thought I was the only one who sweated like that! <actually, all my hiking buddies do too but I'm the only one who admits to it!>
My advice to is to get a really good base layer and don't skimp on cost. I bought some silk long johns for cold weather hiking made by Terramar and wore these to the GC when it was 20 degrees. I layered a short sleeved wicking shirt on top of this and a fleece jacket to top it off and I was actually too warm. By the time I was 3 miles into the GC, the fleece jacket was gone and I was very comfy in the silk and short sleeved top. By the time I was driving down I-17 near Sedona, I was too warm from the silk top and was changing in the car.
Sierratradingpost.com has great deals on Terramar stuff. Silk is the key and wicks the moisture away without making you chill. But you have to layer ALL breathable layers. If you wear the silk and put 100% cotton on top of that.....you'll just trap all the moisture.