Doesn't matter really. Both companies are the top sellers worldwide and make very good products. All things being equal you can't go wrong with either. Just be aware that if you're looking into SLR you should carefully look over the selection and prices of lenses available. For the most part once you pick a brand you're kinda stuck with it for lenses since it's quite expensive to switch systems later if you've already invested alot of money in them. IMHO Canon has a better selection of lenses with some good prices on them.
Just be sure to find one that feels comfortable to use, and you can easily use the buttons/menus. Comfort first, features second, name brand last.
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