I am often asked which camera to purchase by friends and new photographers. It's understandable that you'd want to ask a heavy user what brand they preferred, hoping to maybe cut out days of procrastination and investigation. However, there is no one camera that is suitable for everyone and there are some important points to consider...
Compact v. DSLR
For many people, a compact camera is a good choice. It can fit easily into a pocket or handbag and be ready whenever you need your camera. DSLR cameras are bigger and favored by keen amateurs and professionals. They are more controllable, have the ability to add powerful external flashes, and the lenses on them can be changed for different situations. DSLRs also have no lag between the time you click the shutter release button and when the picture takes. In fact, many DSLRs will take 8 pictures per second without any problem.
Compact cameras are more discreet. I have been challenged many times for carrying my DSLR and told that professional photography is not allowed or no photography is allowed at all even as people with compact cameras have been left to take as many pictures as they wish.
If you choose a compact camera try to get one with a viewfinder. In bright situations it can be difficult to frame a shot using the LCD screen on the rear of the camera. Also, you will tend to hold the camera steadier when framing a shot through a viewfinder.
More megapixels don't make your pictures better, just larger. This is useful if you want to crop a picture and still have enough pixels to get a sharp print. Remember though, that you need four times the number of pixels to double the size of a print. Some compact cameras with large megapixel sensors actually take worse pictures than ones with fewer sensors, because cramming that number of photo sites on the sensor introduces noise into the picture.
I like compact cameras with rechargeable batteries, but you do have to remember to keep them charged and you can't usually put in a normal size battery if you forget. You also need to be sure you have a place to charge it if you are on a trip. DSLRs always have rechargeable hefty batteries and it's a good idea to buy extras of these.
Some compact cameras incorporate image stabilization systems to help prevent camera shake in low light. Make sure this is a true image stabilization rather than just ISO boost. Boosting the ISO turns up the sensitivity of the sensor in low light. In most cases, it introduces noise into the image, which gives grainy and usually unpleasing results. Many DSLRs use image stabilization in the lenses. You need lenses marked IS on Canons and VR on Nikons for it to work. Pentax has image stabilization built into the camera, so does not require special lenses
If you buy a compact camera, try to get one that allows you to set the shutter speed, aperture, ISO, and white balance manually. Even if you do not make use of these features immediately, it's nice to have them as you become more accomplished. An example of such a camera is a Canon G10, but there are many other equivalents.
Using a DSLR does not mean your pictures will be better than if you use a compact camera. The average consumer compact camera has the in-camera color settings, image sharpening, and contrast all set to give you a nice sharp and vivid picture right out of the camera. DSLR cameras are more controllable and can require a more expert level of use to get good images from the camera. However, when you know what you are doing with a DSLR it can produce outstanding images with a sharpness and clarity beyond what you can expect from any compact camera.
There are no bad cameras
Without a camera you can't take pictures and enjoy the art of photography. I respect anybody's choice of camera, but I find it hard to sympathize with a regular post I see in camera forums that says something like, "Shall I buy the Donut 5000 or wait for the Donut 6000, which is bound to be coming out soon?" My answer is always buy the camera now if you don't have a camera. Digital photography is firmly in the realm of all other digital technology in that whatever you buy will be obsolete the day you buy it and there will always be a newer model just around the corner. It will still take good pictures even if there is a newer model around. It might be less painful if you consider your camera an expense and your lenses an investment. In the days of film you would have spent hundreds or even thousands of dollars on film and processing. Now it goes on depreciation of your digital camera.
I've had several digital cameras and can honestly say that in normal situations I cannot tell the difference in the prints I get from them. I cannot look at a print and immediately tell you which of my cameras I took it with, whether it is a point-and-shoot or a DSLR. I can, however, tell when I took them in the context of my career as a digital photographer, because they get better(usually!) . The photographer makes a bigger difference than the camera. A beginning photographer will take better pictures with a cheap point-and-shoot camera than with an expensive DSLR. I have even heard professionals say that their images at first get worse when they upgrade their equipment.
Buy the lens not the camera
If you are a casual photographer (I doubt if you are as you wouldn't be reading this article) you may soon not need to bother about your camera at all, because your cell phone will take all the images you need at a quality you are happy with. I know this has the camera manufacturers worried.
Assuming you are looking for your first decent camera to help you get into the art or business of photography, you are probably wanting some advice on a good DSLR. I don't know a great deal about the smaller brands like Pentax, although I had an excellent Pentax SLR for years, but I know either Canon or Nikon is an easy choice as both manufacturers have an excellent range of quality cameras and lenses. Is one better than the other? I doubt it. Both companies compete strongly and have been around for a very long time. If there was a significant difference in quality one would have disappeared by now.
Camera models come and go with amazing speed. What was the brand new latest thing last week will no longer be manufactured in only a short time. You may decide to change your camera in less than two years, but the lenses you collect will usually only fit your camera brand (I won't go into all the exceptions for now.) It makes it hard, unless you have very deep pockets, to consider changing your brand once you have bought into it.
Not all DSLRs and lenses are born equal
The sensor that records the image in a DSLR is an expensive item to manufacture. To make DSLRs affordable, camera manufacturers use an image sensor in their cheaper mdels that is smaller than the size of 35 mm film. However, lenses were made to cast an image that filled 35 mm film, so in a DSLR you are actually seeing a cropped version of the lens image.
Manufacturers have now started making lenses to go with these smaller sensors, because they are cheaper and lighter than lenses for 'full-framed" DSLR cameras. If you use these lenses (called EF-S lenses by Canon and DX lenses by Nikon) on a more expensive full-framed digital camera, you will not be able to use the full sensor image. So, now there is the added complication of which lenses to buy.
If money was no object I know I'd have a full-framed camera and all the lenses to match. In that way you would have the same experience as looking through the large viewfinder of an SLR. However, even if you have a DSLR and lenses with a smaller sensor, your results can still be outstanding.
The best place for camera reviews is DPReview. Written and maintained in the UK, this website has reviews on all current digital cameras and lenses. It will usually give a full preview of a new model before it is available in stores and includes the ability to compare features side-by-side.
Just do it!
Assuming you have fulfilled your obligations in life - your mortgage is paid, your kids are fed - what are you putting off your camera purchase for? Whether it's your first camera or the latest model you feel you need to have, get on with it, get clicking, and stop reading articles that give camera advice!
Some of the cameras popular with my workshop attendees can be found in the Store Section of this site.