If you are sold on those 2, I would go with the Canon S3IS. It sells for just under $300 and gives you manual controls besides automatic. It also has image stabilization and a 12X optical zoom. It sports just a 6 mp sensor but for the money, it's about the best you're going to find. I shoot a Panasonic DMC-FZ7 with a Leica lens. It comes with similar features as the Canon and sells for around $275. I really like mine and have since added the Olympus 1.7 conversion lens.

As far as position of flash, I don't think you are going to find many options.