I absolutely love my Xbox 360. It has given me countless hours of fun when I would otherwise have been bored out of my mind.
The choice of games is second to none. The experience of Xbox Live is amazing. I can download TV shows, Movies, old arcade games and even content for the 360 games I own to make them even more entertaining. Xbox Live also let's me communicate with my friends with their chat and headset system. I am able to play my friends in different games over Xbox Live.
The controllers are very comfortable and they are wireless. You experience zero hangup or lag when using their wireless controller, definitely a great feature.
The hard drive is huge. I haven't filled mine up and it's the basic model. You can even buy larger sized hard drives incase you really like downloading games and other downloadable content.
I know I won't be replacing my 360 until Microsoft releases their next console, if they release one!