I used to use Monit a lot, but recently started going simpler. We run our entire backend / platform on Heroku, and all our processes are actually DelayedJob workers that run constantly. Using a begin/rescue/ensure we can make sure the "process" here keeps going. It's a little harder to work in a cloud environment, but doing this has saved us from needing any type of sys admin work at all.

It's great using tools like Heroku, who then teams up with awesome other services and then provides great tools to really make life easy as a developer.