I'll start with Rochester, NY: I-490 over the Genesee River.
Hmm, that's an interesting one. It certainly seems iconic now–was built to be, frankly. But it's a comparatively new bridge, even more so than the Interstate itself, and so it has a bit of catching up to do. There's certainly a case to be made for the Broad St. bridge, because its lower level is the former canal aqueduct, and as such it's the crossing most entwined with the city's history. Also, Main St., if never iconic, was certainly noteworthy once, when it was lined with an unbroken facade of buildings on both sides. You don't see that every day, in this country anyhow.
Barring those, the Driving Park Avenue bridge was apparently a big deal in its day. And one bridge that, surprisingly, never seems even to have flirted with icon status is the Vets Bridge (NY 104). I don't know why, I guess it's just a little too tucked away, despite being appealing and monumental and all the rest of it.