I want to be able to take nice portraits of my dd (am sick of going to Sears for their junky photos) and also pictures of our day-to-day homeschooling and family activities, some inside, some outside. I want to be able to blow up the portraits to 8X10 or possibly even 11X14. What amount of megapixels do I need to get reliably good quality picts at those sizes? I have been considering the Canon S2IS but am open to other options. It needs to have good AF but I would also enjoy having the more complex features so I can learn a little bit and do cool things.