There are a lot of features commonly associated with gaming keyboards that are actually quite useful for everyday tasks or even work. Macros can be extremely useful for performing multiple actions in games with one keystroke or even everyday tasks that require multiple repetitive keystrokes. Also having multiple user profiles allows you to keep your work macros separate from your gaming macros.
N-Key Roll Over (nKRO) is also a popular feature, which essentially means that a certain amount of keys can be simultaneously pressed and registered. This is extremely useful around the WASD cluster. The last thing you want to happen is have important skills not register because too many keys were pressed simultaneously.
Mechanical keyboards are all the rage now, and for good reason. Simply put, they're much more reliable than most standard keyboards and are offered in multiple flavors that cater towards specific preferences. Here's a breakdown on the most common mechanical switch types if you're considering a mechanical keyboard:
Blue: Tactile, Non-linear, Clicky, 50g Actuation
Great for typing. Loud (not ideal if sound is an issue). Double tapping can be cumbersome.
Brown: Tactile, Non-linear, 45g Actuation
The middle-ground of mechanical switches. Generally recommended for most games.
Black: Linear, Non-tactile, 60g Actuation
Noticeably stiffer than the rest in order to prevent accidental keystrokes. Generally preferred for FPS games.
Red: Linear, Non-tactile, 45g Actuation
Similar to Browns, but without tactile feedback.