I've had this car for years, a few years ago the coil went bad and I had it replaced at an auto shop. Several months later it started stalling on me while driving. It wouldn't sputter or anything... it would just shut off. When I go to crank it again, it turns but doesn't start. If I wait maybe an hour or two it will crank right up with no problem. What could it be?

Read the sections on ignition system troubleshooting:

https://www.askmehelpdesk.com/cars-trucks/automotive-repair-maintenance-troubleshooting-frequently-asked-questions-46563.html

It could be any of several things; e.g. igniter, main relay, or even ECM. Run through the various tests and you WILL pinpoint the problem. I suspect the Ignition Control Module (igniter) inside the distributor.