I've been thinking a lot about digital cameras lately, as the volume of photos posted here might indicate. Since it's near Christmas (and Boxing Day, for that matter), I thought I'd share some of my general thoughts about digital cameras, and what a year of using one has taught me. I think it's especially relevant right now, because I believe that consumer-oriented cameras have crossed a threshold: they are good enough. Oh sure, they're going to get better (though I think more slowly) and cheaper (though I think that prices will soon be constrained by the less-malleable cost of good lenses than the ever-shrinking cost of good image sensors), but for the usual amateur photographer needs, 5-10 megapixels is probably enough that the lens will start to be a bigger limiting factor in ultimate resolution than the pixel count.
According to my iPhoto listing, I have uploaded more than 1200 items, the oldest from mid-May. Now, that's probably a modest week of photography for some pros, if not a vigorous day, but for me -- and keep in mind I used to be a photographer at my high school, and had unfettered use of one of my father's Pentax Spotmatic SLRs from a very young age -- that may be more photos than I took in the other 31.5 years of my life. This is because of the first rule of digital photography for amateurs: when the marginal cost of taking a picture is so close to zero, you will take a lot of pictures.
Taking a lot of pictures is good for your skills, and a good habit for any photographer aspiring to take better pictures. Sheer chance helps here, too: more photos equals a better shot at getting lucky.
As if that wasn't enough, digital cameras give you instantaneous feedback. It's a bit crude in some cases: I use the rule that a photo isn't really bad until it has been confirmed bad by looking at it on the computer. But a quick check can confirm how the last shot turned out, and hit at how to change settings for the next shot. In traditional photography, the standard method was to bracket and hope. Pros, knowing the value of feedback and being able to justify the considerable cost, used to use Polaroid photo backs for their cameras, letting them check composition and lighting on the fly. Now everyone can have that kind of feedback anywhere. Let's call it the second rule of digital photography for amateurs: instant feedback equals instant learning.
I think those first two rules are pretty uncontroversial. But my third rule is a bit odd: I've come to the conclusion that all things being equal, it's probably okay to sacrifice quality if it means the camera is smaller. Let's put it this way in the third rule: make your camera small enough that you carry it anywhere.
My third rule is born of experience. I like quality shots. But as a person who grew up around several amateur photographers (mainly my father and his sister), we have all noticed that when push came to shove, our SLRs stayed at home most of the time. A compact camera just made more sense in most cases.
To make a long story short, my father and mother now own a Canon A85, a compact digital with a good reputation and pretty good manual controls. My own camera is a Nikon Coolpix 2500, a camera which is mostly pocketable and a mere 2 megapixels. It doesn't even have full manual aperture and shutter controls. But it comes most places with me. If I was to upgrade, rather than move to one of the many really nice cameras in the size range of the very good Canon A-series, I would probably look for another camera the size of mine, such as the Canon S80, or an even smaller option.
So there's my basic theory of digital photography: the first camera an amateur digital photographer buys should be one small enough to carry everywhere, whatever that means for you. I think other considerations come after that.
Since I have you here, let me share my other digital gear theory: the great missing camera out there is an interchangeable-lens rangefinder. Since the LCD screen on the back of digital cameras already offers a through-the-lens display, why not just give up on the pentaprism altogether? Probably not acceptable for pros, but for most amateurs I think the trade-offs would be worth the size and weight advantages. Sony has come very close, and may even be better than my idea (who are you betting on: a large electronics company with years of experience building digital cameras, or me?), but doesn't have a removable lens.
So go get a camera and start shooting. Even a gearhead like me knows that the pictures are more important than the gear. But of course, that's the killer advantage of digital: more pictures. Play to that strength.