How could everyone have ignored Turner? This has always been one of my favorites. Of course, I like marine paintings.
http://www.artble.com/artists/joseph_mallord_william_turner/paintings/the_fighting_temeraire
Note: It was bumped by a spammer, whose post has been removed.
This painting by Ingres
The dress looks like a photograph!
Also, not for its aesthetics, but Winslow Homer’s “Return of the Mistress” because of its “wow” factor: the distinctiveness positions of the women reveal the scene takes place Post-Civil War
I also have too many Impressionists works I love so much.