The evolution of the App Store icon from drawing utensils (pencil, brush and ruler) to transparent popsicle sticks is definitely the most interesting. Ask someone today what the A icon represents, and they would probably have no idea, or think something like building blocks.
Game Center is definitely the worst. The bubbles have never represented anything remotely intelligible. Multi-colored blobs equals games? If you say so, Apple.
I never liked that the App Store icon took the blueprint portion of the Xcode icon, but at the same time it made sense - designing and building apps in Xcode and the finished product in the App Store. Now Xcode uses the same lame elongated capsules.
Game Center is definitely the worst. The bubbles have never represented anything remotely intelligible. Multi-colored blobs equals games? If you say so, Apple.