Large format photography is of great importance to me. The ability to be a an active participant in the photographic process from start to finish is something that is woefully absent from the automation we take advantage of in modern photography, but is required when using Large Format techniques. This dedication to the task at hand makes the photographer work harder for the image- therefore the images captured with these cameras are carefully selected.
These cameras, beautiful in their own right, are a way to achieve even more beautiful images- so long as you know what you're doing. While technical, using a large format camera is not overly complicated. In the end, a camera always boils down to a light tight box. The only thing making a camera a "large format" camera is the size of the recording medium. And working with film is half the fun. Still, large format cameras often offer different tools that most cameras don't have. The ability to use rise/fall/shift to correct for perspective and tilt/swing to manipulate depth of field gives photographers greater control. Even the size of the recording medium alone results in more depth of field control.
Then there's the resolution. 4x5 film can be blown up (or scanned) to very large sizes while still retaining detail. This means wall sized prints are easily created. By the same token, images can be cropped into heavily for a dramatically different composition.
All of these tools are technical, and I use all of them when shooting large format. But the real reason I use large format cameras is the feeling I get when using them. I focus only on the image. Setting up the tripod, composing, setting up the camera, choosing the film, setting the exposure, etc. are all important decisions. Making these decisions alone out in the natural landscape is therapeutic. It calms me- and excites me at the same time.