Good chance that if you have no credit cards/ revolving reporting at all, your scores will drop. One veteran poster lost 20 points. Most of the time, it's good to have at least one card posting an absolutely minimal amount, although I'm sure that there might be some individual cases where this isn't so.
If you want to stop using your cards, maybe you could find a small recurring bill or recurring charitable donation that you can put on one card, allow to post, and then pay off before the due date. If it's for the same amount each month, you could set it up for auto-pay and not have to fool with it at all, other than to confirm that your checking account has been deducted for the auto-pay. That way you're not using it for anything that you wouldn't be doing anyway, and your scores will still benefit.
* Credit is a wonderful servant, but a terrible master. * Who's the boss --you or your credit?
FICO's: EQ 781 - TU 793 - EX 779 (from PSECU) - Done credit hunting; having fun with credit gardening. - EQ 590 on 5/14/2007