One of Dieter's longest longings for the iPhone was the ability just to start typing to search. Just turn the phone on and start typing to launch a device-wide query for all your contacts, emails, events, etc.
Well, it looks like iPhone OS 3.0 finally delivers for him, and all of us. The new iPhone 3.0 Settings > General > Home Button preference page expands on the iPhone 2.0 options of Home, Phone Favorites, and iPod with the two new, much appreciated additions:
Primarily an on-the-go photographer? Just set this option and the Camera is always just a double-click of Home away. Mobile accomplisher like Dieter, choose Search and with a double-click you can immediately start typing in Spotlight to launch Apps or find your data.