In general, smartphones aren't as user friendly (err, idiot-proof) as they should be. That said, MS Smartphones (as opposed to Pocket PC phones, their bigger brothers), Nokia S60 and Palm OS devices aren't all that bad once you spend a day or two getting to know them. Probably Nokia S60 is the easiest to learn if you're accustomed to standard mobile phones.
I'm not terribly familiar with what Canadian carriers offer since I'm based in the US. But for readily available imports there's the Nokia N80 with WiFi, and the HTC S710 Windows Mobile smartphone also with WiFi. You could use an accessory Bluetooth GPS with them. There's also the Palm Treo 750 (Palm did a good job making Windows Mobile more friendly) and on the very high end the Nokia N95 which has WiFi, GPS and a 5MP camera. If you're willing to consider BlackBerry as well, the BlackBerry 8800 is very sleek, easy to use and it has a GPS (but alas no WiFi).
-------------------- Lisa Gade Editor in Chief, MobileTechReview