A desktop or tower case is required to hold all your components together.


What Cases are there?

Case Types

Tower cases are currently the mainstream and are classified as either Full, Mid, or Mini tower cases.

ATX Full Tower Case ATX Mid Tower Case



A Full Tower case is the largest and is able to hold the greatest number of components, but has the largest footprint. Full sized cases are designed for gamers/enthusiasts or other high-end computer professionals who want peak performance and cooling from their machines. Most users, including some gamers, will not need the extra space this class of case provides. 

microATX Mini Tower Case microATX Slim Case

 
On the other extreme, a Mini Towers or an even smaller Slim Case will take up the least amount of space, but their exterior proportions limit the number of components that can be housed inside them. These are cases are only suitable for searching the web, listening to music, and other basic tasks. There small size makes them prone to more heat and lack of space for gaming hardware.

The Mid Tower case's qualities are a compromise between the extremes, and it delivers adequate housing capacity for most computer systems. This median size is the standard because it provides decent expandability without the goliath footprint of full-sized PC cases. Users desiring a computer with room for expansion in the future, but currently do not need the cutting edge performance are well-served by mid-sized cases. 

What one should i get?

Drive Bays

Internal and external devices you are considering on having should be a big factor on picking a case.

Expansion Slots

The expansion slots provided by the case are not that different from those on a motherboard, the expansion slots on the case are designed to match up with the expansion slot positions on your motherboard to secure the add-in cards - and also make connecting other devices to these add-in cards possible. Make sure the case you select provides no less expansion slots than your motherboard has.

Fans

Powerful computers with high-end CPUs and enthusiast-class video cards produce a lot of heat. These computers stand to benefit greatly from the extra heat dissipation provided by case cooling fans. So make sure you have ample amount of cooling when choosing a case.

Ports

Where your ports are located should be a good thing to look at when deciding a case, it is good to get a case that has easy access ports for where you will be putting the tower.

Front Panel Ports  Side Panel Ports

Top Panel Ports  Front Panel Ports

Power Supply

When picking a case keep the power supply in mind. If you are building a budget pc a power supply that comes with a case should be ample enough, but If you are a DIY enthusiast or a gamer included PSU's are usually not recommended. PSU are not a standard when purchasing a case so unless it specifically says its included you will have to buy the PSU individually.