The G2 is notable, because it's an HTC phone with an unmolested version of Android. It's important to note the G1 was not an official Google developer phone, either. You're thinking of the similarly-named, carrier and developer unlocked ADP-1.
Google developer phones:
ADP-1: aka G1
ADP-2: aka HTC Magic, myTouch
Nexus One
Nexus S
Comments
I thought Google's official phones were the G1, Nexus 1 and Nexus S. The G2 is an HTC-only effort, as far as I'm aware.
The G2 is notable, because it's an HTC phone with an unmolested version of Android. It's important to note the G1 was not an official Google developer phone, either. You're thinking of the similarly-named, carrier and developer unlocked ADP-1.
Google developer phones: ADP-1: aka G1 ADP-2: aka HTC Magic, myTouch Nexus One Nexus S