We have one with a nice big credit line on it for emergencies. We generally take it with us when we travel. Its nice to have it there in case we need it.
We have a couple more, but we don't use them. Now we just pay them off.
It can't hurt to get a card and build a good credit history, though. Sometimes no credit history can be as difficult for you as bad credit history. Next time you go to your bank, see if someone there can offer you some financial advice on building a good credit history.