I'd love to see a tool that allows the user to pick a point (default to current location) and overlay rings at specified distances.
Use case: playing outdoor sports the league has a policy that lightning within 6 miles requires everyone to clear the fields for 30 minutes. I want to be able to watch storms as they near that location, and have a 6 mile ring that lets me guess if the storms are going to come close enough to be a problem or not.