I would be very interested to hear anyone else’s ideas here, but off the top of my head I can say that tasks are pretty much the most “disruptive” thing that you can configure to notify the user to take action.
Tasks associated with a particular contact will show up on that contact’s profile page. Additionally, a household tasks view can be enabled to provide the user with a complete list of all pending tasks for the current household.
Unfortunately, tasks are also currently the best way to trigger “next steps” based on input into a form. (Though there is growing conversation around the idea of being able to trigger additional forms).