Personally, if I want want comfy feet all day long on a Spring trip, I go with cotton socks under Gore-Tex socks. It may be because my boots are cold from evaporation but my feet end up dryer and happier at the end of a day then they are right now wearing the same cotton socks under running shoes at my desk.

Could it be those 5 trips across each portage aids in ventilation? ;)

For ankle biters I just drop my pants an inch or two to cover my ankles when paddling. Fly swatters work well for some sandal people I know. Whatever works.