Now that you have decided to build your own computer you will have many decisions to make about what components to use. Since this is probably your first computer build, I will suggest a logical order for selecting your components. Later on down the road if you decide to build another computer, you may choose a particular component that interests you and build around that. But for starters, it is easiest to build a computer by selecting components in a logical order.
The first component that should be selected is the computer case. The computer case is determined mainly by size. Choosing a computer case that is small in size will limit your choices on several other components. Therefore, the case is a logical staring point.
There are several sizes of cases to choose from. They range in size from large towers, known as ATX, to small towers known as micro ATX, to Baby AT to other exotic forms. The case size is referred to as the form factor. Each different case size will require a different motherboard size. Or if you happen to choose the largest case size, then you will be able to choose from several different motherboard sizes.
Case size is somewhat a matter of personal preference. If your situation requires a small towers or a discreet case that can be tucked away somewhere, then by all means choose a case that fits your needs. However, if you have the room for a large ATX tower, choosing one will be beneficial for many reasons.
Choosing a large tower case will allow the widest selection of components down the line. A large tower will allow you to explore many options in terms of motherboard choices, cooling solutions, drive capacity and so on. If in doubt, choose a large ATX tower case. Furthermore, a large case will make the assembly process easier for a first timer.
Now that you have determined your size needs, there are a couple of other aspects of choosing a case to consider. Of course you should consider the color and how it will fit your décor. This is simply a matter of preference though and this choice is up to you. Next you should look to make sure that the case you choose will support your choices down the line. How many hard drives will fit into the case? How many CD or DVD drives does the case allow? If you want a floppy disk, does the case have an opening for it? Does the case have adequate USB ports on the front panel, does it have fire wire ports on the front panel, and does it have a headphone jack on the front panel?
Once you have determined your needs for a case in terms of supporting the devices you wish to use, there are only a few things left to consider. Does the case provide adequate ventilation? There should be ventilation in the rear of the case for an exhaust fan, ventilation on the side of the case for a cpu fan, and maybe even ventilation on the side of your case for your video card and a spot to mount a fan in the front of your case for intake air. At minimum, a case should have rear ventilation and some form of side ventilation.
Once you have found a few cases that meet your needs above, you can now turn to the build quality of the case. The build quality will usually determine its price. Better cases will be made of all metal construction. They are made out of steel or aluminum and will have a sense of heft and quality to them. Lesser cases are usually made significantly out of plastic. Your budget will determine the level of quality of the case you choose.
Now that you have picked a case that is suitable for your computer build, we will turn to filling that case with components needed for your new computer. Please refer to my articles on component selection for advice on choosing the right components.