While I'm thinking about security ... there has been plenty of debate over whether Firefox 3's hostility toward self-signed certs is a good idea.
Either way, this should be a non-issue in the banking world, which ought to have proper certs on any public facing machines.
So I was more than a little surprised when I went through a workflow with Citi, where a number of links, widgets, etc., triggered the Firefox self-signed-cert blockade/warning. The problem resources were loading from subdomains like foo.citibank.com or bar.citimortgage.com.
When I did some work with [insert other extremely large bank here], everything was SSL, even internal web service and app communications, and usually (not for external customers) mutual authentication. The bank had an entire PKI department, which controlled numerous separate CAs corresponding to dev, test, production, different business units/functions, etc.
Hooking up to most things meant sorting out the right kind of cert to present, and working the proper cert chain for whatever the server gave you. In some situations -- e.g., programmatically sorting this out in Java -- it was a major hassle. Not to mention that the PKI group was cooperative but busy, so there could be delays. And the certs were set to expire in not-so-long, so a whole mechanism was necessary to make sure you didn't have system failures in your department due to not getting a new cert placed in time.
It would have been much easier to use self-signed certs all over the place, but the bank wanted some extra protection even against rogue calls from inside the network. The policy made sense and, even if it didn't to you, your alternative was to box up your stuff and leave the building.
Of course intentionally deploying a production service to external customers with a bogus cert was so unimaginable it wouldn't have even been funny ... in order to be funny there would've had to have been some molecule of possibility in it, and there wasn't.
Can Citibank really not have controls that prevent this?