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!
I'm buying the wife an iPhone for Christmas, but I'll never own one myself. I'm too spoiled by the freedom of Android, and being able to do whatever I want with my phone. (rooted custom ROMs, SD Card storage expansion, extended batteries, no need for iTunes, etc, etc.)
