I had the first generation from when it was launched until November 2008, when I traded it in for the 3G. The quality seemed so much better on that first iPhone, with both software and hardware...pre-keyboard lag, anyway.
On this phone the button on the headphones has gone dead, a pixel has been frozen blue since March, and about 10% of the time it takes several presses of the button or a power+home reset to get back home. Lastly, within the past week Google Maps has been crashing almost every time I switch from List to Map or Vice Versa. Yikes!