a lot depends on your budget
remember there is more to the camera than just the megapixel rating
the quality of the lens and ccd means a lot
i once owned a nikon coolpix 2.1 megapixel camera (semipro..it was expensive at the time...like a thousand bucks)...it actually took better pictures then my sony f707 which is a 5 megapixel camera with a "Zeiss" lens...Zeiss is a high quality maker but their cheap lenses for slrs cost a lot more than this entire camera
canon/olympus/nikon are all great makers in the hobby/semipro cameras. sony is ok by my experience. memory sticks are very nice though..much more convenient that flash cards or cds. the flashes suck on these cameras. for casual pictures they will work just fine though
if you step up to the pro cameras (like the canon d60 slr or nikon d1x or n100) you will get great pics but the cost is very high...and you have to buy lenses and a quality flash
also consider the software for photo editing. i have adobe photoshop 5.5 which is unbelievably expensive and not that user friendly.