I'm just happy to receive any card. For me the most important is the contact with other people, not the card itself.
Anyway I prefer postcards with flags and coats-of-arms (emblems, symbols, etc, of towns, provinces, countries). They can be postcards with photos and coats-of-arms, or just with a big picture of the coat-of-arms. They can be used postcards. If possible use nice stamps on envelopes, but it's not very important.
Received cards / Postais Recebidos: