I tend to run "hot" as I follow my dogs. I'm always on the move, blocking doesn't really appeal to me. Oh, I'll block if necessary but I'd rather walk behind my dogs.
So...as has been mentioned upthread, I'll start with just a long sleeve cotton T shirt and cordura faced Cabela's hunting pants, strap vest, usually a mesh baseball cap and light goatskin gloves. This setup will take me down into the upper 40s.
If it gets windy, I've got a Gore-Tex windbreaker to layer over the T-shirt and maybe switch to a GoreTex/thinsulate ball cap.
If it starts dropping into the low 40s/upper 30s, I'll add a fleece vest to keep the core warm.
If it's going to be low 30s I'll use the same setup with a set of light long underwear beneath it all.
If the wind pops up then, I've got a great Cabela's hooded jacket of their Windstopper fleece that pretty much covers me no matter how low it goes.
<Edit> Oh yeah..I also have a pair of GoreTex uninsulated bib overalls for wet weather and/or layering in cold weather. </edit>
My basic view is light is better and layers are key. I've got a heavy duty waterproof storage box with all the extra clothing in it that I keep strapped on top of my kennel in the back of the truck. Easy to layer up or down to suit changing conditions.