I've read all of the comments posted - and working for a major UK bank in their Online Helpdesk I have to say that often customers are to blame for losses.
They have inadequate security on their system and end up with a trojan. Trojan either has a key logger or directs them to a fake site.
Either way the fraudsters typically get their details.
I once spoke to one guy who had responded to 3 scam e-mails in 3 months.
Yes, on the debit card front things do get a little more complex due to cloning and so on, but in terms of online fraud I really do believe that customers should be reimbursed in the first instance, educated on internet security and any further losses is their liability.
Banks take all sorts of measures to protect customers, from SSL and Two Factor Authentication (most banks are currently rolling this out) to using fraud software such as Cyota, and using IP logging.
Most banks also monitor the transactions customers make, so if you usually only make transfers for £50 via online banking, and suddenly try to transfer £1000 that would most likely get the attention of the fraud team.
The bank I work for has recently won an award for its anti fraud strategy - but the bank can only do so much.
If you reply to a scam e-mail, then how do you expect the bank to protect you from that? Customers can yell at bank staff down the phone that we should improve the services, but it's like you giving someone a front door key for your house. Would you blame the police for that person stealing your property?