Choice of a PC case
The case is the only visible element of a computer from the outside. So you need to choose it at your taste!
You must also take care of its characteristics, but nowadays, all manufacturers create good cases, more practical and evacuating a maximum heat. You have still some choices to make.
1°: the material
Steel and aluminium are the 2 main choices. Steel is heavier, transmits less heat, but a little more isolated from the noise.
The size is important! For my example configuration, I chose to go to a micro-ATX case. This forces you to choose a motherboard of the same size, but most people do not need 4 or 5 additional cards in their PCs, so the gain is significant.
3°: power supply unit
The cases are sometimes sold with a PSU. You must then be careful about it, because if the choice of a case is mainly aesthetic, providing a good tension in your machine is essential.
So be sure that your power supply is from a manufacturer mentioned in the PSU article.
Final choice: the ideal micro-ATX case doesn't exist. To my taste, the Lian Li PC-A03 was very good, but Lian-Li has stopped its production. You can go for its big brother, the larger PC-7FN.
Les cubes sont sympathiques, comme Advance A-cube ou Antec NSK1380 (c'est en fait le même boitier, mais Antec ya mis une alimentation, un bon choix) ou Lian-Li PC-V351 (beaucoup plus cher, mais Lian-Li est une marque réputée de boitiers, l'aluminium est plus épais et résistant).
The cubes are nice, as Advance A-cube or Antec NSK1380 (it's actually the same box, but Antec has put a PSU, a good choice) or Lian-Li PC-V351 (much more expensive, but Lian-Li is considered as a solid cases brand, their aluminium is dense and resistant).
If the choice seems too limited in micro-ATX, take one from the smallest standard ATX cases.