One of the new features of iOS4 is custom wallpaper on the home screens. This idea came from the iPad, which on the iPad looks amazing. This is because there is more screen real estate. On the iPhone however, the icons are much closer together and it starts to look a bit cluttered.
I’ve found that reverting back to black is actually quite visually appealing.
Also, I’ve made a custom logon type lock screen. It can show your avatar, your name and “if found” details.
Cluttered home screen:
Classic home screen:
Custom logon screen: