I never was a big-screen kinda guy. I didn't ever see that as a reason to upgrade, I wanted a physical redesign...just because change is interesting, and keeping the same thing gets boring.
My friend, a manager of the Best Buy Mobile, got a free Galaxy S2 a couple of days ago and I messed with it last night and I have to admit, having that screen (I think it's a 4.3") is absolutely awesome.
So, if Apple goes full-retard and releases a "4S" type of device, I will more than likely get that S2, and then when the actual upgrade to the 4 comes out, I'll use an early upgrade (pay $400 or so) to get the iPhone 6.