Hi,
I could advise you to use the just released bitcoin debit card. Since it is Visa branded, I do believe that its security has been put into the right path. Visa is a brand for very many debit cards today and through the experience, I believe that they are doing a great job. However, you should not restrict yourself to that particular option. There are always very many option and all you need to do is have enough research about the wallet. This information can be found through the reviews and comments that are usually available online. From that content, you will be able to find the best option for your coins. Be on the look out that you wont be conned.
What debit card are you talking about? There are many Bitcoin debit cards. Some of them will take directly from the balance you deposited into whatever online service it is from while others you need to load by sending some amount of Bitcoin to a specific address.
I think the wallet with the highest security is Bitcoin Armory with the cold storage 2-pc setup. I don't particularly trust hardware wallets like Trezor since you can't know for sure if the hardware maker somehow put in a backdoor. Paper wallets are also a good option for securely storing Bitcoin for a long time.