Seeing the first few answers I realize the importance of this question in relation to the times we are facing now: a world-wide depression. It is understandable that most people like their pennies, I would say.
When I asked the question I was thinking in terms of its practicality as a coin. I see a price of 89.99 for example and I know they are holding-off that penny just to influence the buyers' mind. One may be inclined to look at a product priced at 89.99 and think: "Eighty or so dollars is not so bad", when in reality the item is practically 90 dollars (or whatever currency you wish). Pennies don't help as a coin.
Sure every penny is worth something but it's usefulness as a coin I think is declining.
Just an opinion. Thank you for your answers.