When selecting a tree to plant, there are a lot of variables to consider - mature height/spread, soil needs, climate, fruiting, aesthetics, etc. Luckily there are a number of online tree selectors that can do the thinking for you. You simply put in the variables (or as many as you know) and the selector spits out a list of trees suitable for your planting location. Below are 5 of my favorites. These work well for the Upper Midwest, but can be applied to many other parts of the country as well. The University of Florida Selector is my favorite of the bunch, but all will work relatively well.
1. University of Florida - http://lyra.ifas.ufl.edu/NorthernTrees/NorthernTreeSelector.swf
2. Minnesota Department of Transportation - http://dotapp7.dot.state.mn.us/plant/faces/index.jsp
3. Arbor Day Foundation - http://arborday.org/shopping/trees/treewizard/intro.cfm
4. University of Illinois Extension - http://extension.illinois.edu/treeselector/
5. Morton Arboretum - http://www.mortonarb.org/trees-plants/tree-and-plant-advice/tree-selector