I appreciate everybody's comments and opinions.
My insurance adjustor says 90% of roofs here just use 2 or 3 turbines. Apparently there is some resistance to ridge vents - maybe appearance, or some other concern. Well, maybe they a just a little cheaper.
I don't know the proper terminology. The only vents I have now are big vents at each end of the house just under the peak of the roof. So no matter what I use, the circulation is probably not going to be ideal, but it seems that the ridge vents may be better. Anyway, thanks again for the help.