Security will be a major issue but no more of an issue than for electronic banking.
Are you kidding ?
In "electronic banking" there is almost no way anyone can steal significant amount of money without beeing caught and the money recovered.
Security is THE issue when dealing with bitcoins. Especially with bitcoins that you have promised to keep for somebody else.
Are you kidding?
People steal funds electronically all the time.
Sure, Bitcoins are harder to trace but do you think the banks have thought, "You know what? Let's just make our systems slightly secure. We don't want to make it too difficult for people to steal money."
No, what they've done is strike a balance between security and convenience.
Sure, you could make it a requirement that you need go into the bank with a DNA sample to make a withdrawal. That would be damned secure but ultimate completely impractical.
Bitcoin could be made 100% secure, it would also be 100% inconvenient.
So yes, securing Bitcoin will be no different to banking.
Recent losses on credit cards amounted to $190B - if it were that easy to trace, surely they wouldn't be losing so much would they?