I think that hybrid strains are probably the most valuable, even for commercial growers. People seem to like characteristics of both in their product. It's hard to beat Skunk#1 in terms of saleability. There are few strains that I know of that reflect so well the general desires of the public for day-to-day use, which obviously means sales to commercial growers. Haze has been steadily overshadowing Skunk for quite a while now though.
So, in short, I say 50/50 hybrids are the most valuable. I've heard people say they don't like the lethargy sometimes associated with a full Indica, and I've heard people say they don't like the raciness or sometimes paranoia of Sativas. It just kinda depends, yuh no?