Digital is fantastic ... for proofing
No this isn't a troll, however it is a serious post.
Like many photographers, or it may just be me, the image I sometimes see in the viewfinder/screen is not quite what I remember the scene to be.
My wife has a Canon A310 - a digital equivalent of an instamatic which I have started carrying to "proof" sites prior to photographing them on film.
The advantages I have found are as follows.
 Quick walk around the area -- just shoot anything that is interesting.
 Quick transfer into the GIMP and reduction to greyscale with a preset black and white filter to approximate the film paper look I have. The reduction to greyscale is very handy as it helps understand the scene in a B&W way.
and  the ability to crop and examine image alternatives within things that have caught my eye.
Something else that I have found useful is the fact I can look at the image on the computer devoid of the distractions of ambient noise, smells and other sensory input. I have often been dissappointed with an image because it failed to convey all the emotions of the location. I don't get this naturally when viewing another photographers work of course and "proofing" in this manner away from the location I can look more at the image for what it is not what I felt at the time.
My wife has had this camera for quite awhile now and it has had little use -- until now.
I've often said digital is a great light meter too. In fact due to another thread, it might be an even better film scanner. Hmm...good for proofs, excellent light meter, decent film scanner...there might be some usefulness for digital afterall!
I use a digital camera for taking pictures of signs, so I don't have to carry a notebook everywhere. That's the only use I have found for one.
This is the first time I have ever seen anyone mention this obvious use for "that" type of photon harvesting device. To KNOW before you leave what the correct exposure for a scene should be. If you can correlate the correct exposure from one media to another, it would save a lot of frustration in missed exposures. Think of it as polaroid without the muss and fuss.
This thread is dangerously close to being way off topic, but I like living on the edge.