I tried a Saddlemen's gel pad the first year I had my bike. It certainly absorbs the ambient temperature. If I left it on the bike in the sun, it was unbearably hot to sit on.
I'm going to give the Alaska Sheepskin another shot. Don't really need it but it might be nice to have. I just ordered the nose strap as my only problem with it is it flops back when I stand up and is a major pain to get it reset before I sit down again.