There is no greater purchase protection than that which comes with a credit card. If when you say Debit Card, you mean a Visa or Mastercard debit card, you get the same protections as someone with a Visa or Mastercard credit card.

It is EXTREMELY important that when you add such a card to your PayPal account that you add it as a credit card, and NOT as a bank account. While PayPal will offer you a mild form of purchase protection with either, this protection expires after 45 days. If you used your bank account, this is your only option at dispute resolution. HOWEVER, if you funded the transaction with your credit card, the issuing bank will likely provide you with up to 12 - 18 months to make a dispute, Paypal be damned. I have had two situations where Paypal dispute resolution failed me, once due to their ridiculous un-appealable decision, and the other due to the expired time frame. In both cards, my bank refunded my money.

The only other tip I'll offer is what some have mentioned about whether the payment is "Personal". Many sellers ask that you do this as they don't have to pay as much fees. DO NOT DO THIS, as there is a strong change you will forgo your bank's dispute resolution process. YOU WILL CERTAINLY FORGO the PayPal dispute process.

If someone offers this, tell them no and that you'd rather pay extra to cover their fees. May just charge a blanket 4%. If you want to be a stickler, the formula to use to generate the amount to pay to avoid fees is:

(desiredFinalAmount + .30) / (1 - 2.4%)

or

(desiredFinalAmount + .30) / (1 - 3.4%)

If it's a cross-border transaction.

I find just paying the 4% is better than being a stickler and well worth the protection.

Lastly, credit/debit cards have other protections too that make them a much better idea than bank transfers. These vary across providers, but my NAB Gold Banking Visa debit card offers:

1. No currency conversion fees
2. 90 day accidental loss / theft / damage protection

IMO, the only purpose to having a bank account linked to your paypal account is to withdraw money.