The legendary Cadian regiment of the Imperial Guard are depicted above you in pitched battle. When I was 13 I started playing the Imperial Guard units, most notably the Cadian Guard units. I feverish collected, painted, and glued together hundreds of guardsmen, around six tanks and numerous support squads. The guard units have so many customization options. You can customize everything from their gear to their stance.
In recent years Imperial Guard players have shifted from their legendary and noble guard armies to less noble armies such as the Tau Empire and the undead, machine Necrons. These two sides are less than noble. The Tau are a collection of super suit soldiers, with no customization, and the second-class citizen speices Kroot. While the Necrons are sell-out, noob friendly, the children side. The Necrons and the Tau might be the flavors of the year, but I sincerly hope that in future years players will come back to the Guard.
The guard have been the powerhourse of the Imperium for thousands of years. Forget about the childisih, space marines, pick up a guard unit. The guard are your average-joe-soldiers. They might die in masses, but I perfer that kind of valor over the ridiculously overpowered Space Marines. The Imperial Guard side fight with nobility and many are legendary units such as General Gaunt and his partisan Ghosts.
The Battle of Cadia was the single most defining moment in the Imperial Guard's history. The Cadian Gateway to the Eye of Chaos is the single most defensible position in the Imperium. It is in this sector that many brave soldiers from Cadia are shipped off world to fight for the God-Emperor and the Imperium. If the Eye of Chaos falls, the Imperium falls.
The history of the Guard is rich, notably the Cadians. As Imperial Guard players we need to unit to combat the threats of child friendly sides such as the Necrons, Space Marines, and Tau. We need to unit as players of the Guard.