Sorry, really boring topic! 
Have recently moved house and not sure what to do with them. Last house we were in, there were rather ugly (slatted) bannisters going upstairs from the living room and we blutak'd the cards to them - looked very nice.
This house is dead refined, has staircase in the hall and everything!
Living room has mantlepiece (already taken up with candles, German wooden Christmas figures and photos) and no windowsill (arch through into dining room instead). The doors are sort of eggshell so I suppose I could blutak cards to them but not keen.
I used to see those sort of adhesive ribbons in the shops, you pressed the cards to them and they stayed stuck.
Haven't seen them for a while, though. Anyway, shops are a drive through the snow away! I could make my own with some ribbon and glue dots (but would ruin the ribbon for future use).
Any other tips? You can buy all sorts of display stands (again, a trip to shops) but they don't seem to offer much room.