Shadows under Control
One of the most difficult aspects of HDR processing might be to achieve a good balance between shadows and highlights, as well as a enough level of detail in those areas. The presence of well defined shadows and highlights helps to maintain the mood of the original subject, and that can be lost by the use of most HDR operators, which strive to present as much detail in the shadows as in the highlights, resulting in a very flat illumination throughout the photo, one of the aspects which as certainly contributed in the past for HDR bad reputation.
In the photo above, I tried to keep some of the deep shadows and preserve the original highlights in order to keep the mood of the room where I was taking the photo.
You can compare that with the result obtained in the second photo by carelessly using a popular HDR software. In the second result, the flatness of light is noticeable mostly on the floor, which is almost deprived of shadows. Although both results might have their aesthetic values and appeal to some public, I personally prefer the first result.