Last week Andi, a beginning photographer in Australia, asked me to identify what technique one of his competitors was using. It didn't look like an ambient shot, it looked a little like flash but not completely. It was clearly flash and ambient blend. Some call it exposure blending in Photoshop.
You will see people in the PFRE Flickr forum talk about this technique or refer to blending an ambient image and one or more flash images together. As you can see from the tutorial above this is a very powerful technique. You can combine the best aspects of several images into one image.
The YouTube video above is by Simon Maxwell, an Architectural photographer working in the UK illustrates how to use exposure blending to carefully control the color balance in an interior shot. Simon now has 4 chapters in the newest version of Enfuse and Hand Blending in Photoshop For Real Estate Photography that go into detail on this powerful and popular manual blending technique. Controlling color balance is just one aspect of this technique.
Exposure blending is something you typically use for a project where you have plenty of time for post-processing. Since you could spend 30 minutes or more on a single image so this is not a technique I recommend for a typical real estate shoot where you are under tight time constraints. That said, I hear a surprising number of folks talk about blending images.