My buddie has the Cannon SD500 or 550? He had an older one and now has the brand new model. They are both AWESOME cameras and I have a $6,000 digital SLR(set-up) that I compare it to. I have high standards when it comes to image quality. The new model even has an underwater white blance setting, we shot some pics of his 300gal (16, 4' VHO's) which usaually renders a wierd blue glow in photos from heavy actinic. The corals had never been captured so accurately!! And on land the pics are amazing too. I always thought I liked Nikon better because of the quality of the Nikkor lens but, for point and shoot, those Canon's are hard to beat. I also have a friend who got the Olympus, I can't remember the model but, hers actually goes underwater up to 12' WITHOUT a housing! I have only seen it outside and have not taken any tank shots yet but, it seemed worth looking into, as it had 3 diff underwater settings too.