First of all, 38000 congratulations to you! You have done an amazing job!!!!!
Second, ditto on the cash advances--don't do it. Fees fees fees.
You should decided whether you intend to pay cash for the next year or if you consider a credit card safe to have. Given that you've paid off $38K, I think you'll be ok with a credit card, but that's for you to decide.
I would only ever hold one card that has an annual fee otherwise you're wasting your money. I have a Southwest airlines card because that's what we fly (though I really should have a card for an airline that will take me to Hawaii instead :). Then, I'd only keep that card if you intend to buy things on the credit card to maximize your return. If you're only going to use cash here on out, no use paying for a credit card.
I think you should keep at least one card for online purchases (airline tickets etc.).
We have three (well four), credit cards:
1 main card (with annual fee) we take out of the house and use all the time
1 card solely for use on recurring internet purchases that I don't want to have to reenter should the house card get stolen
1 backup card for travel.
1 Kohl's card, because I buy clothes at Kohls and in theory you get more % off if you buy with their card. I'd been putting off getting this for 5 years, because I do like having my wallet simplified.