D4 vs D800

Since I am a surgeon, I will "cut to the chase" with my question. I intend to retire in about 18 months and I am really looking forward to spending time learning to be a much better photographer than I am now including the post processing. This will be what my wife and I do together. I have been investing in the best lenses because I know from my reading that they are such a key component of your equipment, especially with the increasing megapixel world in which we live. I am looking to make a decision as to the camera body that I will use in retirement. I am fortunate to be in the position that I can afford either one but do not want to spend money for the sake of spending money. I like all types of photography including landscape, family, buildings, macro, etc. I have no intention in doing portrait/studio type photography although I would like to know how to photograph people well. As our grandchildren get older and are progressively involved in sports, I will want to photograph them indoors and out. Video will likely not be a big part of what I do but I won't know until I try.

That being said, the D4 would seem to be more of a "known entity" as it is an incremental improvement over the preceding high end FX cameras. The D800 is a whole new category of camera with some similarities to a medium format camera. Until such time as it is released and delivered and tested in the field, there is only speculation as to how it might perform. I recently spoke with Scott Kelby and asked him his advice. He will have both cameras but he told me that most of the time he will be using the D4. He said that would be his choice but that, if there wasn't a hurry to make a decision, I might wait to see if Nikon is going to bring out a true upgrade to the D700 which is what I was really anticipating. I apologize for rambling but I am interested in whatever wise counsel you might give me. Undoubtedly, it will be varied but I will value the opinions of those who choose to respond.