If you still have the 3GS, then the 4S is a MUST upgrade! I have the iPhone 4 and still want to upgrade. But I'll admit the move from 3GS to 4 was bigger than 4 to 4S. The fact that it's not called iPhone 5 means next year's is going to be even more significant. But the 4S (and iOS5 and Cloud) is quite impressive. I've had an iPhone since they came out, and have had every model except the 3G. Love it!