If there were negative interest rates, wouldn't you either switch banking providers, lose faith in the currency (and get some pretty hefty inflation), or take your money offshore in a different currency?
As a consumer, I don't like the idea of negative interest rates. That said, I can see the advantages in them. The housing markets prices would skyrocket - as everyone wouldn't try and save for a house, but try and purchase one immediately. I think instead of negative interest, interest at a lower rate than inflation, or zero interest, would be a better option.
I'm not so sure about an all digital currency, it'd open everything up to hacking, and those movies where the intelligence service drains the bank account would result in the victim having nothing, rather than just cash. I quite like having cash in my hand, rather than numbers in an account, don't have or use a card personally. I wouldn't expect the US Federal Reserve to be one of the leaders in the field - they seem more conservative, and I doubt Joe Hillbilly, or even Joe Sixpack for that matter, would be too happy about physical currency being phased out.
I don't particularly follow the financial markets closely, but I've seen enough of Bitcoin to be convinced that (I didn't realise there was a Nobel Prize in Economics) the founder(s) of Bitcoin would deserve an Nobel Prize in Economics - not in the next few years, but after the technology begins to snowball.
The paid NS army is a scary thought. Although we would get a much higher uptake on the forums here if we were paying people to do it, although the average post quality would likely decrease (but the quantity would skyrocket). I'd think we'd prefer NSCoins to have a higher value, approximately one NSCoin to one US cent - unless we're intending to pay $100 US to every new member.
Then again, I've seen founders/regions banned for similar things, such as a virtual off site currency in NS where you could pay real money to gain the currency, and get homework done for you etc. - the real money bit is the problem. That's why you can only gift stamps, you can't ask for anyone to do anything back after you gifted the stamps.
Just imagine how many WA votes Bitely would have... (He's had his month, now he's vanished back to obscurity again)