Kids, families, proms, seniors

If you're considering using it for business (you can write it off) part time and then FULL time, buy the most camera. True the feature set difference is small, but the the difference is in big areas IMO (that's why it costs more). You'll want 19AF points, shorter lag times, faster write times (CF vs SD cards). Weather seal may not be that important to you. And besides if you ever upgrade to a 5dmk11 or a mk you'll be able to use your CF cards...then again you may have some SD cards from your rebel use. note action shots...you'll want more AF Points, they could be difference between that winning smile.