There’s not much to admire about today’s city street sign; it does its job—namely, letting you know where you are—without much artistry or design.
But judging by some late-1800s photos, street signs used to be more ornate and had a few Victorian touches, as this 14th Street and Fifth Avenue picture reveals:

By the early 1900s, it looks like the Victorian flourishes have disappeared, at least on this sign on Fifth Avenue and 45th Street:

In the 1960s and 1970s, street signs were downgraded to simple rectangles on an unadorned post painted dark yellow. Occasionally you can still find one that hasn’t been replaced by the more contemporary brown or green sign.
This one at Union Square still stands; somehow it escaped the Department of Transportation sign-changing squad:

Sometimes street signs contain spelling errors, like this one here. It was fixed a few days after the misspelled sign was put up last April, but jeez, Mercer is not a hard one to get right!