Crows can recognize people and remember them for years. Listen to this interesting report from NPR. Researchers alienated a crow, and then were razzed and harassed by its family and neighbors wherever they go.
Related: Cool Crow Research – Friday Cat Fun #10: Cat and Crow Friends – Smart Crows

This was a fascinating story, particularly the part about recognizing the mask when worn upside down. Reminds me of the reverence some native American peoples showed the crow. They must have at least sensed this ability, since being scolded while hunting would hardly be a successful strategy for survival.
That is very interesting.. I actually just finished watching some youtube vids about how smart they are.. Pretty amazing!
http://www.youtube.com/watch?v=BGPGknpq3e0&NR=1&feature=fvwp
http://www.youtube.com/watch?v=03ykewnc0oE
I can even say that Crows, and especially ravens, often feature in European legends or mythology as portents or harbingers of doom or death, because of their dark plumage, unnerving calls, and tendency to eat carrion.