I don't understand the big fuss over rounding in the discussion of eliminating the penny. Rounding happens. We already round sales tax up or down to the nearest penny--this would just round up or down to the nearest nickel.
But while we are on the subject, I think we should eliminate nickels and quarters at the same time as the penny and just round to the nearest dime. (Let's put the 50 cent piece of of its misery while we are at it too--just dollars and dimes). Rounding to the nearest ten cents is plenty specific enough given the accumulated inflation/devaluation of currency over the years and you basically get to simply knock off one decimal digit of precision for each transaction which makes things more straightforward. Also, US dimes are small and lightweight, making them easy to carry relative to other coins.