Iphone has a lot of fancy feature but the stuff i liked the most and which could be copied easily by others is wallpaper settings on iphone.
If you watched the keynote video of Steve jobs at macworld. You would have seen that half way through the presentation he changes the pixar fish wall paper to a boy's face. You say what's special in that.
Here is what i saw, he selects a photo and zoom on to the face of the child and sets it as wall paper. what does the iphone do, it makes the wallpaper of what was on the screen rather than the entire picture. so when he switches the phone back on again you can see the boys face as wall paper and not the whole photo as wallpaper.
This is such a simple feature why didn't other phone manufactures think of this. For example i have nokia n70. unless its a full resolution 2 mega pixel photo taken by the camera or a photo that is exactly 176X132 size photo it doesn't show up well on mobile wallpaper, anything in between shows up with color borders.
So nokia are you listening copy this and put it in your next firmware for n70.