Here's a list for you and those of us who neglect to mention them:
-Siri
-8 megapixel camera with vastly improved optics. Quality is absolutely outstanding. I am a pro-photographer, I use Nikon and Canon DSLRs, I shoot films on the RED and I can tell you the iPhone 4S camera is far from mediocre. 1080p video on a camera that does not look like $#!T, AND almost no color noise in well-lit photos. Amazing and worth the upgrade for me.
-A5 Chip, dual core processor. Talk to anyone who games on their iPhone, talk to me who uses the Brushes app and other creative tools. This particular upgrade makes Brushes, Games, and productivity apps run smoothly, and when I'm digital painting on my phone, I don't want the cpu to hiccup.
-improved antennae design. I get 1 more bar everywhere I got less than 5 bars with my iPhone 4. It makes the difference.
-Bluetooth 4.0.
And lets talk about the design a little. Stainless steel. Last time I checked, stainless steel is stronger than cheapo plastics. Glass. Beautiful, reflective, smooth, polished glass. My finger glides across it like a puck on ice. Used the Droid Bionic and Droid charge (Friends). It was like touching sandpaper with a burn wound.
Cheers.