I'll sound off:
I've found absolutely nothing wrong with the build quality of this phone.
It feels solid like a tank in the hand, the OLED display hasn't exhibited any dead pixels and generally it feels like it could take a beating (haven' tested this..!!).
Long story short -- I'm amused because my news applet keeps popping up stories with headlines to the tune of "nexus one huge effing dissapointment", however if you read the body the point is:
Sure, the Nexus one is the fastest android cellphone with the most vibrant screen. Sure it's backed by Google and will most likely remain on the cutting edge of OS updates. BUT -- some people (ok, a bunch, but I'm not one of them) are having 3G issues, and _oh noez_ Google didn't do _enough_ with this phone to make it worth while.
Ok -- I've gone on a tangent; it's late and I'm tired.
tl;dr:
Built like a rock. No issues whatsoever.