This depends a lot on the person. Personally I don't need much. Even down to about 25*F, I'm wearing a poly compression top, T shirt, and a windbreaker layer (usually my rain gear, which is vented) up top, and just shorts and a pair of cheap lined running pants. Even at 0*F, I just add a sweatshirt and a pair of long underwear and a pair of wool socks over my regular socks.

And at that, I'm sweating. But I sweat regardless of the temp if I'm exercising; at -20*F I get to work sweaty with near frostbit skin, and a warm core.