It looks like one of the new features of Android 4.0 Ice Cream Sandwich will be the ability to support USB gamepads.
You’ll need to get an adapter to get your full-sized USB controller working on the micro-USB port supplied on your phone, but afterwards, native controller support means much smoother gaming times when you want to play a mobile game with a traditional controller. Honeycomb already offers USB controller support, but Ice Cream Sandwich will be the first time support is built-into Android smartphones.
What do you think? Can you see yourself using a USB game controller to play a game on your phone?