Starting in the Middle
I have a confession to make - I don't have all the stuff I'm supposed to have as a digital photographer. To my mind at least, I should have extra lenses, lens hoods, filters (other than my circular polarizer that I don't use very much), external battery packs, more books on photography, more studio lights and other photographic stuff that I don't even know exists yet. Nobody ever claimed photography was an inexpensive way to spend the time.The way I look at it, there are three ways to start with digital photography: at the top, at the middle, or at the bottom. Truly starting at the top requires a not so small fortune. To get everything for the perfect setup would take more than most people (myself included) want or can afford to spend. Starting at the bottom has its problems as well. Getting the cheapest of everything generally leads to markedly inferior results.
What's the solution? Starting in the middle. This means having a mix of good quality longer-term items and inexpensive temporary solutions. In general, the things that should be good quality are the things that cannot be borrowed, worked around, or inexpensively replaced. To my mind, it's often better to find a work around than invest money in something with limitations that will make it need to be upgraded in short order.What do you need to be a digital photographer? For starters - a digital camera. It isn't necessary to get a top of the line professional camera, but don't skimp either. Figure out how big you want to make prints, what features are a must for you in camera, what flaws you are willing to live with, and what you can afford. Settling for something that won't make you happy will lead to a lot of frustration. You simply can't get good results if you don't start with a decent camera.
In order to power the camera, you'll need batteries. If you plan to shoot on a regular basis, you will want rechargeables and a charger. Figure out how fast you go through batteries and how often you'll be able to charge to determine how many you will need. Even if you aren't shooting that often, rechargables are far more cost effective in the long run, but running with disposable batteries is an option, and many cameras can be powered by an adapter in a pinch.
In order to capture photos, you'll need memory cards. Unless you want to cart along some form of portable storage device, get enough memory to last you a whole session. The card that usually comes with a camera is generally only good for about a half-dozen photos at the best settings, so you'll need to buy more, but getting one or two additional small cards is a way to keep expenses in line until something more is affordable.
If you are willing to use camera store kiosks to download your photos, burn them to CD, and print them, the above list is the only hardware that is absolutely required. Most people will want a little more control than that over their photos and will want a computer with lots of RAM and a CD burner (for archiving) and a printer (preferably six-color). It doesn't make sense to skimp on these, since they can be borrowed, worked around, or are something that people interested in digital photography often have (especially the computer).Both editing and archiving software tend to cost quite a bit. Free or less expensive software may be a solution until you can afford more advanced programs. Using what's already available may not yield the best results, but it may tide you over until something better is affordable.
All of the additional hardware is optional, although there are limitations to what can be done without some of it. These items should be purchased when you feel the limitations of doing without them and have the money to get good quality.
It isn't necessary to buy a professional camera bag, but you will want something with small pockets and lots of padding to protect your camera. Getting a small, less expensive bag lets you have one you can keep packed to grab when you want a quick shot. Neck straps that are comfortable keep your camera a lot more secure and are far less likely than the common wrist strap to accidentally bash your camera into a wall.
For photos with long exposures, panoramas, or use with macro and telephoto lenses, a tripod or monopod is a must. Tripods should let you pan the camera in any direction, and monopods should fold up into something small enough to be carried conveniently. Both of them should be lockable into position, or it defeats the purpose of having one. A substitute for them is a wall or table.Studio lights and external flashes cost a small fortune for good quality. Depending on your choice of subject, they may be important or you may never need them. If you do need more light, bright household lights may give good enough results to get you by for the time being when you are just starting.
Lenses and lens hoods can let you take wide-angle, telephoto, and other shots not possible with the zoom lens on most digital cameras. How necessary they are depends on what kind of photography you do, but I haven't found much in the way of inexpensive replacement. The effects of many filters can be simulated by editing software, so this is another item that can wait.
A memory card reader is useful to download photos faster and allow you to shoot while downloading and a portable storage device can be used to carry large numbers of photos. External battery packs are one way to not worry about running out of battery power, but they are often both expensive and heavy. All of these items can wait.
The start up costs of digital cameras are more than shooting film, and few people can afford to start with the best of everything. Starting on the bottom generally leads to disappointing results. Looking at what you already have and deciding what is most necessary for the kind of photography you do lets you start in the middle.