One of my favorite plug-ins is Nik Color Efex Pro. I started with a basic version years ago and worked my way into the complete version. I've always enjoyed the variety of effects that the filters provide. There are filters like White Neutralizer and Pro Contrast that might be all that is needed for certain images such as the church above. There are filters that work magic on skin such as the Dynamic Skin Softener as I used below on the Quinceanera. Plus there are a lot of fun filters for creative effects such as Midnight, Monday Morning or Solarization. Make great pictures!