sRGB or Adobe, CMKY or RGB, what is DPI? Before and after the shutter has been released, a photographer is presented with a vast number of options that affect both the picture quality and appearance. It would be an easy thing to flick the camera to Automatic mode and happily snap away in the knowledge that the camera is doing all the thinking for you. But if you are interested in taking your photography to the next level and want to compose pictures or bring them to print, a degree of understanding is needed to prevent mistakes that could have otherwise been easily avoided.
First let us consider the debate of jpg vs RAW file. A few years ago, I was lucky enough to spend a couple of weeks deep in the Honduras jungle, conducting field experiments. At the time I was only a casual photographer and so only had a few small sized SD cards handy, with no laptop or portable hard-drive. In this scenario, I decided to use jpg instead of RAW, because it enabled me to continue shooting all the way up to the end of the two weeks without running out of space on my cards. The low file size of the jpg is one of the major advantages that the jpg has over RAW files. A typical jpg can be around a 1-3 MB, where a RAW can be 2 or 3 times larger than this. There are various technical reasons for this, but the only one you really need to know about is that the RAW file captures all the information from the sensor (including a higher dynamic range), while jpg doesn't, which is where the strength of shooting in RAW really lies.
I always shoot RAW these days, not only for its ability to capture all the information on the sensor, but largely because it is a loss-less format, meaning that I can edit my photos to my hearts content and the image will maintain its quality, where a jpg will deteriorate with every edit you make. This even includes making minor changes, like a quick contrast change or rotation.
You may be reading this and thinking that RAW is definitely the choice for you and largely, I would agree that it's the format of choice, however, there are some minor drawbacks. For instance, because of all the information it takes in, it takes longer for the camera to record a RAW shot than jpg. For landscape photography, this may not be a problem, but if you are an action or sports photographer, you might want to factor this in your decision. Another problem that I have encountered on various occasions is the issue regarding compatibility with computers. All the different brands of cameras have their own RAW files and certain editing software have notoriously had problems in opening some of these. Recently, I tried opening a few Nikon NEF files in Photoshop CS5 and encountered errors. While this is easily solved with download-able plugins or updating software, it renders RAW files unsuitable for sharing with other people, who may not have the correct version of software to open it. If you don't own any editing software or have no intention of editing, then jpg is for you since it is a universal file that can be opened in most software. It is also sharper and has a higher contrast than RAW files, which can look slightly washed out without appropriate tweaks.
So to conclude, in almost all cases, it is better to shoot RAW, as you will have a greater control over the final image and safeguard against any mistakes in the camera (eg. a quick colour balance in Photoshop to remedy a dodgy white balance). After all the editing is complete, the final image should be saved down as a jpg, which is an ideal file for end users and clients due to its compatibility and relative small size. If you are still having difficulty in choosing between the two, I recommend you find the setting on your camera that allows you to shoot both jpg + RAW, since this will allow you use the jpg photos immediately and should you wish, come back to the RAW files in the future for post production.