I am not upset at what I paid, I only bought the 8GB @ $599 because I thought it was worth it.
It just sucks that the price drop happened so soon and was so dramatic. It would be like buying a $50k car, and then in 2 months the manufacturer drops the price to $44k for the same car, killing your resale value of the car.
But seriously, $200 off? That just sounds excessive. $100 seems like the next logical price drop amount. If trends like this continue, it would make me personally rethink when I buy Apple products. I don't have to buy there stuff when it first releases. I do it because I expect the value of the product to remain the same for more than 2 months after I buy it.
No regrets here, I am still happy with the phone and everything, I'm just unsure of Apple's motive of such a drastic price drop (especially with all the new iPods released, I'm sure they would have no problems selling the iPhones at the old $499/$599 price points).