Pioneer Square Station on the Seattle Transit Tunnel. Note that the primary users of this tunnel are *buses* -- the light rail system only launched in 2009, over fifteen years after the tunnel opened. These are probably the nicest designed-for-bus stations I've ever seen.
Rosedale Station in Toronto was a surface station on the original Union-Eglinton section of the Toronto subway, opened in 1954.
Pixellated public art at Sheppard-Yonge Station, Toronto.