I have trained virtually with some of the industries best real estate and architectural photographers, and have mastered a process known as Flambient, where indoor photos are taken with ambient only light, then with studio flash, and combined in post-processing to provide a highly realistic and appealing representation.
The Flambient process is far better than the HDR process most real estate photographers in the area currently utilize, either due to the lack of knowledge of the Flambient process, or due to the speed advantage HDR provides (shoot and scoot mentality). HDR results in flat and muddy color, and can leave ghostly artifacts that make for a visually confusing image.
Here is an example of the Flambient process:
This photograph was created using the Flambient process. Compare my result with the photo used in the current MLS for the home: