very tempted with willow....
Remember with willow that once it's in... it's there for ever. The harder you cut it, the harder it grows back. I chainsawed a neighbour's shrub/tree down to a low stump (with permission!) and within a year it was 15' tall with stems of an inch thick in places. Incredibly fast growing but you don't want it anywhere near foundations.
If that's not a problem, willow fedging is attractive, easy to do and cheap (free if you can find someone like "Me" who will let you cut the whips for them)