I collect decks of cards and books. And when I say collect cards, it's not like the card collections you see on youtube where that have 17 packs of blue bikes, one tiger deck, five decks of ghosts etc. I just buy one deck of any cards i find, not just uspcc stuff. Then they go in a cool case i have and i don't use them. I just bring them out to show people if they are interested. Not sure how many I have at the mo. Probably somewhere in the region of 30 different decks.
As far as collectables go, I have first editions of Derren Browns 'Pure Effect' and 'Absolute Magic' (now out of print and worth about £300 each!), a signed Andy Nyman DVD, a signed Dynamo DVD and a playing card signed by the legend that is Rene Levand.