Pecan is a type of hickory, so you get the hickory flavor, but in a little lighter form. And another advantage of cherry that I love is the gorgeous red mahogany color it gives to meats.
I also like the Lumber Jack "Competition Blend" (also called the MHC blend). It's a combo of Maple, Hickory & Cherry. Since there's less hickory in the mix, it gives a very similar, slightly sweeter profile as a Pecan-Cherry blend. It's my favorite mix for smoking sausages.