I don't think circulation coinage will have key dates because of such high mintages. Did the 2009 P nickel become the new 1950 D?
I don't know why our lifetimes would be any different. Look at the 1995W ASE. Looks like you already have one is my guess. Or a 1950 D Jefferson.
The 1994 and 1997 matte proof nickels and the 1998 matte proof Kennedy half seem to be very very underappreciated... perhaps they will gain some popularity in the future if people see them as part of a complete set (which they should). The 1996-W Roosevelt dime is pretty cool too, but like the above coins, just about all of them are in great condition still so it'll likely never rank up there with the big key dates.
I am not sure about key dates but some of the quarters from 2009 and 2010 have lowest mintage since the 1950's. TC
