It's tough to say.... the 2 HTC phones i've had (HTC Hero and HTC Incredible S) have both been very good. However, the reason i've waited this long to get a new phone is because of numerous reports/reviews citing issues.
The nexus one i believe suffered from poor screen brightness, making it difficult to see in bright lights, and some of the dirt under the screen.
The Desire HD had awful battery life and some reviews stated that the battery casing feels very flimsy and breakable.
As you say, the simple fact is that the design and quality of materials is still higher than the main competitors. My other options were Motorola Atrix, which i didn't go for because it's locked to AT&T, and iphone 4, which i didn't go for because i genuinely preffered the look and feel of the incredible s, plus i have bought quite a few android apps!
I think most users are spoilt for choice nowadays... a lot of really great phones coming out this summer.
If you want to wait for it iPhone 5 or the next iteration of "Nexus" will probably be my top choices, followed closely by the Moto Atrix.
lol... that was longer than i was expecting!
Good luck! IS won't let you down in terms of build quality. If you can wait, get iphone 5, nexus x(whatever it will be called) or moto atrix.