Sycamores! There was a big sycamore back where I went to school that I liked to sit up against and read. I like birches because they look really cool. And fruit trees! I think we should plant a bunch in cities for people to eat from as they like.
I always enviously eye people's fruit trees and vines, I wish I was closer to a community garden. I've seen some posts about guerilla gardeners planting food crops in nature strips. Unfortunately, I live in a place where people would either take them all, or throw fruit at cars.