Just my opinion (and we all know what that is worth). I would NEVER plant a willow tree let alone by the waters edge. They are just a mess dropping branches after every little wind and uses lots of water.

I am in the same place after reworking the north side of my pond and doing alot of thinking about this right now. The area I have to plant is roughly 3/4 acre. My current plan is to keep all trees atleast 30' form the waters edge and 30 to 40' from the spillway. Starting at 30' from the waters edge I am planning on 2/3 red maples and 3 river birches. Next 50 - 60 feet from the water I will have a couple of white oaks that I raised from acrons this year in roottrappers. After that I am finishing it out with one to two rows of Norway spruce or blue spruce or combination there of. The spruce if in 2 rows will be spaced 40' apart and the rows space 20' apart. All of the trees will be alternative in the rows so they don't line up from row to row. I have a layout of this just not here at work so will have to post later.