Admittedly, I am a digital photographer. Also, I own only one digital camera so I can only add observations on my experiences in digital photography.
Firstly, the digital experience isn't simply about cost. Nor having a ready vehicle for posting pictures on the web. It's about complete control of you photographs, from the moment you shoot until the moment you print.
Also, if we are going to compare digital cameras to film cameras, lets make sure we're comparing apples to apples: Just as there are point and shoot film cameras, there are also digital cameras built for that market. Manual shutter and aperture on a point and shoot would defeat the purpose. And best of luck attaching an external lens to one.
"Granted, memory is a one-time investment, however, it is a very expensive one that may cost more than the camera itself for a reasonable capacity of high quality photographs."
Really? It cost me $100CDN for a 64M stick (suitable to store up to 60 pictures which can produce an 8x10 print to rival a 35mm film print.) The camera was $1699CDN. So unless I plan on taking 600+ pictures in one sitting, storage cost will never exceed the cost of the camera.
"Most cameras can do 640x480 (and thus it is a reasonable benchmark) and get about 5 pictures/megabyte "
Not that any self-respecting digital photographer would dare shoot in that resolution, but while playing one night, I managed to stuff 326 640x images on a 32 meg stick. Storage requirements depend on image size and image compression.
I proceed from the assumption that ideally, the objective of photography in general is to end up with a picture, in some format, that can be viewed.
Thus, consider the cost of developing your pictures with a film camera, as well as any possible duplicates you might want printed as well.
With digital, there is no need to print. In fact, I have shot over 4,000 pictures with my current camera. 60 have been printed. At the cost of 1 CD-R (I would say comparable to 1 roll of film) I can make available hundreds of pictures. Not so with film. Because the storage medium is reusable, if you don't print your pictures, the memory sticks pay themselves off in no time.
If we are to compare both mediums, we must assume that we have all the necessary equipment to a) Take the picture b) Develop and edit and c) Print. If we are going to compare costs, we should assume that you've included the expense of building your own darkroom as well for film photography. Don't forget the "reasonable quality slide scanner."
"The information about how many mega pixels a camera can do is all well and good for nice high quality wallpaper or screen savers."
I can't say I've ever run my monitor at 2160 x 1440. Mega pixels have nothing to do with computer display. That is how many picture elements are in the image. Film prints are generally done at a resolution of 301 dpi. In order to create a print from a digital image that will equal in quality that of a film camera, that is the magic number. A 640x image will produce an impressive 2 inch print. So mega pixels are of paramount importance.
"...the most authentic way is with the camera itself."
Is your writing less authentic now than it would have been 20 years ago, using a pen and paper?
How is creating a double exposure with Photoshop less authentic than doing it with a film camera? Sure, you can't accidentally make a double exposure with a digital camera. But if you had intended to create one in the first place, what does it matter when or how you do it?
Digital photography is relatively young, but is maturing quickly. And as it matures, prices drop. Comparing a film camera to similarly featured digital camera, the initial cost is higher. However, unlike film cameras, digital is a format that pays itself off.
As for only using digital for snapshots, well, I would have to disagree. With manual focus, 5x zoom, shutter (8" - 1/1000) and aperture (f2-f8) priority I've got more than enough flexibility to create very high quality prints and images. Oh... and I can shoot 15 seconds of motion video if I so choose. Then again, you could make a flip-book from your prints.