I'd wait and see if they will indeed charge for 4G first, than based on that make a decision. Im in the same boat as many others, Im in a no 4G area. So if they do charge more for it, I might very well consider grabbing a 3G phone that might be cheap and use it for a year, maybe the Droid X or the Incredible? I dont know lol.
The Incredible is much cheaper than the X, $100 new, $50 used (2yr contract).
But get the X if you can, my Incredible just lost 3G and the best I have been able to get is 1X- after research, I discovered people have been having issues with the Inc's radio.... And the speaker tends to blow, not on mine- but if it doesn't blow, you've got a pretty decent speaker. And the optical trackpad button... What for? The LED is only three colors- red, orange, green. The stock battery sucks...
But unlike the X it actually fits in my pocket, and it supports VzAccess Manager, most people probably don't care about that one haha.