I'd sway towards the Canon G3.
1. Cheaper. You really don't need 5+ megapixels if you're not planning to print out big prints. The money you save can be put towards your car.
2. Longer warranty. My digicam just broke and I'm paying $400 to fix a $800 camera. Warranties are good. Don't know about them being valid in Canada though.
3. The review from http://www.imaging-resource.com
mentions fewer photographic flaws with the Canon. Probably not something any of us would notice though. You can check out sample images from each camera at that site as well.
What are you using the camera for? The G3 and 5700 are high-end stuff.