I gave this question a lot of thought, and I have three bags in vintage styles that I equally love the most. Only one is actually chronologically vintage, so I'm going to add a couple of near vintage honorable mentions.
My favorite truly vintage bag is my nwt 1996 Madison Biltmore in scarlet. I keep being tempted to cut the tags and use it, but I've been able to resist so far.

My near vintage honorable mentions are my 1998 Pearlized Satchel (as best as I can tell, this is the correct name, even though it's a tote) in lavender and my 1997 Madison Gracie in an unknown (to me), but perfect, primary shade of blue.
Although these three bags aren't made of the thick, glove tanned leather usually associated with vintage Coach pieces, they do share the the clean, simple but elegant aesthetic that vintage Coach pieces are known for. What is so special to me about these bags is that they are, for mass produced items, fairly unique, and all three are beautiful and timeless. Without knowing their ages, you might not even know that they're as old as they are. Similar styles to the Biltmore and Gracie have been in continuous production by various brands for a very long time. The Pearlized Satchel has an Art Deco feel to me, and it has the "wings" that have been trendy for a while now (but I don't hold that against it

). Coincidentally, they were all made in Italy.