I would pick my app carefully. Things that are specific to desktops like AV, disk cleaners, performance monitors would have staying power. Also word processors for specific constituencies. Scriviner, for instance, is for serious writers and is still supported by its creator. Diagram creators, slide presentation creators, even a database with an easy to use interface would be popular.
I personally would love to see an enhanced Activity Monitor for Mac. Something that would have an entry for every process running so I could just click it to figure out what it does.