Fascinating thread. What we are trying to decide is rather philosophical; when does a photo cease to become a "photo" (with all of the documentary baggage associated with that concept) and enter the realm of "art"? For me, unless your photo is going to be used as evidence in court (where ethics demands a high degree of correlation between the image and the state of the universe as seen from the point of view of the camera at the time the shot was taken), then the ultimate objective is the reaction to the image in the mind of the viewer. Moving the camera 3 feet to the left to hide an ugly sign behind a bush when taking a landscape photo is no more or less valid as an image altering technique than cloning it out in Photoshop after the fact. Airbrushing Aunt Suzie's hideous facial wart is no different than having her turn her head slightly to hide it. In all these cases the "reality" of these images could be called into question, because they fail to tell the "whole truth"; they sin by omission, as it were. Neither landscape image would suggest the existence of the sign, and neither portrait image would suggest the existence of the wart. However, no photograph can possibly depict every possible detail of every element of the environment in which it was taken, so this is not an indictment of any of the hypothetical images described.
Much of photography involves choosing what to photograph, and which vantage point and field of view to use. This has more of an effect on the finished image than any other factor, regardless of whether one is using digital or film, and regardless of the means used to process the image. The choice of subject, vantage point, and when to capture the image makes all the difference between a ho-hum snapshot and an Ansel Adams. My personally preferred approach to removing the sign from the landscape image would be to move the camera; not because it is any more "truthful", (although it is, from a certain point of view) but because moving the camera a few feet is less hassle than trying to get rid of the sign in Photoshop.
I enjoy photographing sunsets. I could create vividly colorful sunset scenes in Photoshop without bothering with my digital camera and all of the other accoutrements of digital photography, but I find manufactured images to be less interesting than ones with a reasonably high degree of correlation to an actual location and event. In pursuit of the goal of creating images of sunsets that have a significant basis in reality (which is a personal preference) I carry around a camera and tripod and devote considerable time and effort to recording images of sunsets that I think are aesthetically pleasing. When people look at my work and ask if the sky really looked like that, I tell them that the brightness, contrast, and color saturation may be adjusted somewhat, but the image depicts with a reasonable degree of accuracy what the camera saw when the image was recorded.
Likewise when taking a portrait, I try to capture the personality of the subject without highlighting their shortcomings, real or imagined. This process involves selecting the environment, clothing and perspective for the shoot, selecting the image from the shoot that that has the most pleasing facial expression, and occasionally airbrushing acres of acne. None of the images may correlate particularly well with what you might see when the subject is asleep and wearing curlers and no makeup, but that is not the point of portrait photography.
In general, I find the task of defining whether an image is "real" or not to be an endless morass of legalistic quibbling. If an image with a gamma adjustment of 1.2 is still "real" what about 3.2? Is B&W photography "real"? By any objective methodology of measurement, it has a lesser degree of correlation to "reality" than color photography, but I have never heard anyone dispute the "reality" of an Ansel Adams landscape print. How far can I turn up color saturation before an image is no loger "real", and who is going to send the color police after me if I exceed the limit?
If someone purchasing a print inquires what techniques were used to create it, don't be dishonest, you can always refuse to answer the question if you think they won't like the answer. Hey it works for magicians, why not photographers? Come to think of it there are a lot of similarities; they are into sleight of hand, we do sleight of eye. Anyway, I've ranted enough for one post, so I'll shut up now.