The case is the housing for your system, it offers protection against the elements and can either hide or display the inner workings of your PC.
ATX form factor is the current standard for motherboard/case layouts. Before ATX there were AT cases which handled the early 8086-Early Pentium systems.
Cases can be bought in different sizes such as midi towers, full tower, server tower and desktop cases. However the common options are either mid tower or desk top cases. You may consider either depending on the place of use so that you can achieve better use of space.
If you are regularly inside your PC swapping things over or testing things you may want a larger case to allow you more room to get things in and out more easily and to give you extra space for additional drives.
Cases start from £10 and climb to well over £100 dependant on the materials and the rated power supply. For a typical mid tower case with a Power Supply (PSU) you should be looking at around £40min.
You can go cheaper but we would not advise you do so mainly as cheaper cases can be poorly made and are not finished correctly. As a result the case can be dangerous to carry or when installing hardware your fingers could be sliced on rough edges.
It is for the reasons previously that most builders will pay extra for a branded or well built case as they know it will be finished well and has good specifications and features.
PC Cases are still available in some places in Beige, however it is possible to find a case made from Steel, Aluminium, or Plastic in a variety of colours in various different shapes and sizes. Some may come with extra features such as Window Modifications for those so inclined. A lot of cases now include at least five drive bays as standard with ports to connect Firewire and USB via the front case panel.
Every system needs a Power Supply (PSU) to bring their system to life. These have also evolved in a similar way to the case market. Before they came in standard casing and were rated at various low speeds of 200W, 235W or 300W. With systems now running at over 4GHZ and with muliple cores/processors, with faster motherboards, faster power graphic cards and additional devices power supplies are now available with ratings over 800W.
Most PSUs come with built-in fans to help keep the components cool and working efficiently. Although the size of PSUs has not changed greatly they are available in various colours often with coloured fans.
We would recommend a supply of at least 350-400W dependant on the type of user/use. And of course for higher end systems a higher supply.
Prices for PSUs are around £20, but it is worth paying a little more and opt for a branded supplies as they are often tested more thoroughly and often come with a warranty and are sometimes quieter than cheaper units.