I carry my CitiCards credit card.
At home I have cards for Discover and Capital One that I don't use. I also have open accounts and no cards for Wells Fargo, TrueCredit and Chase (I always cut up the new ones they send me).
I swear I have one more, but can't remember what it is.
I tried taking the Discover card out for a while, but 3/4 of the establishments I tried to use it at didn't take it. Sadly I was on vacation at the time with no other card on me!!! So needless to say that one always stays at home now.