I believe visa/mastercard credit you are liable for $50 in fraud, or less.
Some debit cards offer similar protection--for example, my wife bought some fake jewelry in Mexico a few months back, paid with her debit card, and CapitalOne was able to reverse the charges, or just refund the money--I'm not completely sure if CapitalOne got repaid or not.
The problem with debit is that it's pulling "real" money from your account, while a credit card is just a "credit", or debt.
So the risk of using your debit card is one of fraud. Paypal is a widely used, widely respected merchant/bank/whatever, and they're not going to empty your bank account.
Just link your bank account to paypal, you'll be fine. I've had mine linked since about 2004.
