Smartphone cameras are the new, ya know, real cameras, and iOS 5 is gonna make the iPhone's camera a hell of a lot easier to use. First and foremost: HARDWARE SHUTTER BUTTON. Baby bay-bay.
No more curling your finger around to tap that ill-placed on-screen button to snap pix. iOS 5 will let you push the Volume Up button to take photos instead. For those of you who had this feature briefly when it was an Easter egg in the Camera+ app - a feature that caused Apple to unceremoniously boot Camera+ out of the App Store until they nixed it - you'll know how great the hardware shutter button feels.
Other improvements! A shortcut that jumps directly to the camera app from the lock screen. Will come in handy when you're trying to capture your kid or your cat doing That Really Cute Thing. Also, pinch-to-zoom in the camera live view; touch Auto Focus and Auto Exposure lock; and cropping, red eye reduction, and quick-enhance in the app for sprucing up pictures.