With the ease of genetically modified plants, we will begin to see plants created that are multi-functional. For example, when the DNA is infused with the glow-in-the-dark DNA from some ocean creatures, your hallway plant will be a night light. And you will be able to throw out your Glade Plug-ins to keep your air fresh. A plant that is engineered to do so, will not require electricity -- just light and a bit of watering occasionally.
I predict that some plants with wide tropical leaves will be engineered to absorb sound in places like shopping malls and public areas. Plants will be enhanced to filter out and clean air. They already provide oxygen and eat carbon dioxide.
Our future will incorporate plants into our bio-system which will perform better than their mechanical or electrical counterparts. So while we await these miracle plants, lettuce rest -- I feel beet.