Up here in Canada, all prices are still in penny denominations but when you get to the register, and pay in cash, it is the cashiers job to round things up or down to the nearest nickel. If you pay electronically, you would still pay the sticker price down to the penny - therefore making the psychological aspect of pricing still valid since most people pay this way.
If one were to be obsessive about it, you could use debit for all transactions where the price would be rounded up otherwise, and cash for those that are rounded down. Thus saving a few dollars a year. That would be some kind of sick individual though, I imagine.