Games
Like other gaming consoles, the Xbox gaming library consisted of games from various genres including (but not limited to): first person shooters, role playing games, fighting games and sports games.
Controllers
When it was first released, the Xbox came with a rather bulky controller that some referred to as the "fatty." There was a lot of unused space on the controller, with an angled button layout that some found uncomfortable. After heavy criticism, a smaller, more sensibly redesigned controller replaced the original.
Xbox Live
A year after its release, Microsoft introduced Xbox Live; the Xbox matchmaking and content distribution service. Those with a broadband connection and an Xbox Live Starter Kit (sold separately) could play select games with other players via the Internet.
Voice Chat
Voice chat was a mandatory requirement in games that utilized Xbox Live. The Starter Kit included a behind-the-ear microphone, which could be used to talk to other players in-game or in specialized chat rooms.
Xbox 360
The Xbox 360 was the successor to the original Xbox. While it shares traits with the original (such as its large size), it puts more of an emphasis on Xbox Live connectivity, includes a wireless controller and more support from third party game developers.