Canoe2fish,Go with the metal valleys,and ice@water under it,and on your eaves to.With the weave in the valley the leaves will stay in the valley,and thats what you do not want,with the metal valley the leaves will have a better chance of flowing off than the shingle weaves...and like MTP said DON,T forget the Drip edge.Are you doing the job yourself,or contracting it out.All you need to make your valleys look good is make sure you chalk line the valleys,and that will give you a nice finnish.What is the pitch of your roof.
Steve