This was a fun research project for us, a quick internet search reveals more about computer case's than you would ever think.

When you find the case "you just have to have" then check which mainboard from factor it accepts before ordering, once you are armed with the form factor information then research your mainboard choices to determine the right system for yourself.

Case modding is the artistic styling of computer cases, often to draw attention to the use of advanced or unusual components.

Apparently there is a market for Pink computer case's, aluminum computer cases, acrylic computer cases, clear computer cases, custom computer cases, gaming computer cases, mini computer cases,  rolling computer cases, full tower computer cases, quiet computer cases, small computer cases, water cooled computer cases, atx cases, atx pc cases and even sunami cases!

  Water Cooled Case.

A desktop case sits flat on the top of your desk with the monitor situated on top. This was the style of IBM's original PC, XT and AT models. These early desktops were fairly large and bulky, taking up a lot of real estate on the desk.

The resulting trend was for manufacturers to make them smaller and more compact. Unfortunately, as you make the case smaller, things inside get a little crowded. Access to the different components becomes much more cramped, cooling is a lot less efficient, and there's less room for expansion. Desktops usually have two or three external drive bays and 1 or 2 internal bays.

The Slimline case is even smaller. It's shorter, narrower, and looks a lot less bulky on your desk. This is about the only appeal these machines may have. Slimline computers are very proprietary, not well cooled at all, and have about zero room for expansion. Slimline usually have one or two external bays and one internal.

The tower case sits on end, taking up less square area space and offering a better variety of sizes than a desktop. It allows for a lot more choice as to location, depending of course on the particular size. It can sit on the desk beside the monitor, on a separate shelf, or on the floor beside the desk. On the negative side, it should be mentioned that cases on the floor may be more prone to kicks and bumps and in some locations, the cords may have to be extended. Tower cases have much better air flow, better accessibility to internal components, and (except for the micros and ultra low end models) allow for more upgrade and expansion capability.

One company's mid-tower might be another company's mini-tower.

What you need to know before buying a new computer case:

•  Form factors describe the size, shape and general makeup of a hardware component
  
  As of 2007, the most popular form factor for desktop computers is ATX, although microATX and small form factors have become very popular for a variety of uses..
   
•  Form factors of motherboard, power supply and case must match!
  
  Otherwise you will blow your budget trying to find the right parts that will fit into that shiny new case!
   
•  Motherboard drives the decision
  
  Find the mainboard you want first then research the case.
   
•  Matching form factors assures;
  
  1) Motherboard fits the case
  2) Power supply provides correct voltage and connects to the board
  3) Holes in motherboard align with case
  4) Holes in case align with ports in motherboard
  5) For some form factors, wires for switches and lights match with connections on motherboard
   

Form Factors in detail..

Power Supplies