1. Financial services will re-evaluate the risks of this kind of attack vs. the cost of assigning more resources to guard against it.
2. Governments will finally start taking IT security seriously.
The latter is the more interesting, because while banks are generally reasonably clued up about balancing risks and will simply adjust their current practices, elected representatives who aren't technically inclined will probably be discolouring their underwear over the fall-out if the bad guys really tried to do some damage, given that it is this easy for a few upset people to cripple the world's payment systems.
I suspect that as a reuslt, we can look forward to increasingly draconian penalties being introduced for this sort of action in most jurisdictions, the end of on-line anonymity as it has been known, and ruthless throttling/disconnection of entire ISPs/countries that don't play ball with either of the above. If you thought government reactions to copyright infringement were heavy-handed, I imagine they will look like a nun comforting a child compared to what is coming next.
The sad thing is that better security, robustness, user authentication, etc. should have been built into the Internet by default for years, but the same "Wild West" evolution that was so successful in the early days has also been a poor driver of consolidation now that the Internet isn't just a toy for the military types and the universities any more. Maybe the Powers That Be will finally start taking serious advice about IT from people who know what they're talking about and collectively give the issues the attention they deserve. (I won't hold my breath, though; this could all end in tears, with a mess of ill-informed and poorly-implemented measures that cause all kinds of additional dangers to innocent people without actually fixing the real problem.)