I currently wear trail runners for all my hiking. The drawback is that trail dust filters through the mesh tops and my feet get filthy. But blisters are now a thing of the past!

On backpacks, I wear ankle-high merino wool socks in a lighter weight. They happen to be REI brand, but that seems unimportant, since they fit a fairly generic type made by most makers. A major consideration for me is how quickly they dry, because I wash my socks daily on longer backpacks and they need to dry easily. Merino wool dries well. The other consideration is just to provide a bit of cushion, which merino wool does well. They wick and breathe well, too.

In addition, I use cheap thin nylon 'dress' socks as liners. They seem to last forever. They dry very fast, too.