I never use a debit card for anything except a bank withdraw at the drive thru window. My reasoning is a debit card is a direct pipeline to your savings/checking accounts, I try and insulate my accounts as much as possible. My credit card is from a different institution that I have no accounts with. I also use my CC for any automatic monthly payments, I don't want my trash company or phone carrier having access to my accounts.My daughter does the same.. she uses her cc's almost exclusively because she gets loads of points back etc.. also she says it's so much safer than debit cards.
I use my debit cards for every day purchases.. but online and for purchases over £100 I always use a Credit card, because there's security behind that..whereas there's none with debit cards