It's a big deal: even Google noticed that today is the last day which the Canadian Mint will be issuing pennies. The copper plated steel coin cost 1.6 cents to make, and they were piling up in drawers across the country. The mint explains:
The decision to phase out the penny was due to its excessive and rising cost of production relative to face value, the increased accumulation of pennies by Canadians in their households, environmental considerations, and the significant handling costs the penny imposes on retailers, financial institutions and the economy in general.
Cash registers are being revised to round up or down to the nearest five-cent increment for cash purchases, but not that many people will actually notice; Canadian credit cards all have a chip in them and for purchases under C$ 50, you don't need to do anything but tap your card on a terminal. Many people don't carry cash at all.
See a great infographic on the penny at the National Post.