I have 4. 1 is a 128 card that my ex got me when he got me my point and shoot. I bought a 1gb shortly after that to hold all my pictures from Hawaii. So that's 2 cards.
When I got my D80 last May, I bought a 2gb super awesome fantastic one.
For Christmas, Jordan got me an 8gb card cuz I wanted to start shooting in RAW.
So, 4. But I only use 2 at a time (one in the D80 and one in the point and shoot that stays in my purse). Everytime I copy pictures from the card to my laptop (and EHD), I reformat the card and wipe it clean.
I would like to get 2 more 4 GB cards for the D80 if/when I get into serious photography.