It really isn't easy to say what the best insoles are, because they are the best insoles for you.
I've got flat gel ones (good over orthotics when I run, Superdrug ones), memory foam (nice and soft bit big but squash well, 99p from one of the pound store type places), I've tried sorbothane and noene and others; I used to use Superfeet before I had custom orthotics made. The boys have Sorbothane in their walking boots (the ones with arch support) and love them.
It also depends on what your boot will take, because altering the insole will alter the fit of your boot. Take your pick.