Rails, and all the Ruby ecosystem has to offer, coupled with Postgres.
When a project becomes even more complicated and it looks as if Rails with Resque/Sidekiq won’t cut it, I go with what we (team on any project) all decide to use for certain parts of the stack. Whether that be Ember/Backbone/Angular on the front or Scala/Go for certain workers, Debian or CentOS on the server, etc. or what not.
My personal preference won’t mean anything if a project goes bigger than me. I value working with other people over technology choices, even if the collectively-decided pieces of the stack were a little different from my own stack.