The Steam Controller
I got in on the first pre-order
It is pretty darn cool.
There are two trackpads that give a haptic rumble when you use them like your phone when you type. They are also buttons.
The wings underneath on the battery cover are also buttons. COmes in handy so you do not have to take your thumb off the trackpads to jump / reload. (pic below) They are made to make it fel like a PC gaming experience like using a mouse and WASD.
Folks say it takes a bit to get used to over normal gamepads, but for me I never really used regular gamepads and it just feels right. Aiming on a gamepad frustrated me.
I plugged it in and right away I was using the trackpad like a mouse and surfing the web with it. Super cool
You still have the analog stick, but this is super customization with keybindings and the left trackpad can function like the analog stick easily.
Portal 2 is awesome with it