i think there is a difference here:
if you get given something directly from a player, or bid on it for a charity event... then you will have a sentimental attachment to it (supposedly), and thus, should keep it.
if you buy something on from someone else, then really, it just becomes a jersey with some scribblings on it. ifyou catch my drift.
with regards to whose jersey would you want... i would happily give a good home to any players jersey. the fact they gave it to you as a present should be respected in such a way. but then again, i horde everything, some people sell on clutter. differing mentalities i suppose
sorry if that has already been said