The solution to all the world's problems

The three word answer? Abolish paper currency. If there were no paper money and all financial transactions were conducted directly between personal, institutional and governmental bank accounts then there would be no scope for money to change hands without leaving a trail.
Politicians could not accept bribes in secret, criminals would not be able to steal or profit from illegal activity, charitable contributions could not be siphoned before they reach those in need, terrorists would not be able to get their funding without exposing their patrons. In short, the world will be a better, though slightly big-brotherly, place.
Certainly there are pitfalls. All the fringe illegal activities that we indulge in will be curbed. No buying soft drugs, no bribing the maitre de for a good table, no friendly gambling, no prostitution (not that I advocate it, but I'm pro free market on everything), no cheating on your taxes and no underage drinking. And if you're a beggar - tough break pal, get a job.
But I think that it's a small price to pay for an incorruptible government, a dis-incentivized criminal population and the disappearance of black money from the third world.
Sure the logistics are massive, but technology makes it easier and cheaper than you would think. Every human being would have to have a centralized bank account and a small hack-proof wirelessly accessible memory device to store their account information. When a financial transaction has to be made, the payee would enter a passcode into his device to view his account balance, select the paid party's device (in a similar manner that bluetooth enabled cell-phones currently recognize each other), select the amount to transfer, confirm the transaction and he's done. The device synchs up with the central bank using the nearest Wi-Max network and everything is squared up.It will be a large initial cost, especially to get the technology and infrastructure in place in the poorer parts of the world, but once it's done the rewards will more that pay for themselves.
Why am I rambling on about this? I just spent half an hour rummaging through my desk drawers to come up with the change I needed to get my afternoon sugar rush out of the office vending machine. When I got there I found that one of my coins was a Canadian quarter that the machine disdainfully returned to me while keeping the rest of my money. Time to move on I say. I've had enough.