destination ideas?
 

Is there a site or app where I can put in an airport and a range of miles and it generate a list of destinations/airports to fly to?

If you're based in the US, you can try http://www.google.com/flights and enter your departure airport, then use the sliders to adjust for things like price, number of stops, and trip duration (semi-related to distance).

FareMap has something similar, it takes an airport and shows all the fares from it.

You can select the "zoom" for your map which roughly controls for distance, tho with flying distance can be misleading depending on your routing.

http://www.farecompare.com/maps/

A range of miles? Is this for your own plane, or did you want commercial service?

You can create a quick "x miles around a point" map with this tool, and compare it with the airport destination maps available on Wikipedia. Many airlines (e.g., AA and US) use an online mapping app that shows destinations from a point and allows you to sort them by mileage.

Not range of miles, but Kayak.com/explore lets you tell it the airport you want to start and how long (time wise) you want the flight to max out at, so you can get pretty close to the range you are looking for.