I chose the Nikon over the Canon. Reasons: Nikon include a set of rechargeable batteries and a charger unit, Canon don't. Plus the Nikon camera has an additional "mass storage device" mode that lets the computer access the files on the camera directly. Canon's camera supports only the standard PTP mode. So the Nikon will be easier to handle on computers that don't have the camera's drivers on them (read: other people's computers, Linux machines).
The only things that the Canon does better are direct connection to printers (PictBridge supported after firmware upgrade) and video recording (the Nikon does not record audio).