I'm pretty much a "go native" tree planting kind of guy! Thus, I'm not a big fan of planting little-leaf linden (overplanted) or ginkgo--just my personal preference as I'm a traditional dirt-forester, not an urban forester.
Sweetgum (non-fruiting variety) is a legitimate choice, as are various oaks, hickories, blackgum, baldcypress, Kentucky coffeetree (male), Freeman maple, cucumbertree, etc.
There really are no perfect species; just make sure to choose and plant > 2-3 different species. Mix it up a little and get rid of some of these drab urban monocultures :-)