Buying organic vs. buying locally

My kids have a thing for mangoes, more like an obsession really. They can eat them faster than I can peel them, and "mango" was one of my younger child's first words. Here's the thing, though -- mangoes don't grow where I live...ever, which means that to get a mango it must be driven or flown here from somewhere else.

When our family started eating more organic foods, it was mostly for the health of our children. Our kids go through an astonishing amount of produce for two small children and I was concerned about the levels of pesticides they were getting. But I try to be an eco-conscious consumer as well and can't help but hear the debate between eating food grown organically and food grown locally. This article talks about consumers who've been brought up to expect out of season fruit on their grocery store shelves, and I'm one of them. I'm used to eating strawberries and mangoes and starfruit, even in February. But this debate gives me pause and makes me wonder if I should be taking a harder look at my habits, especially when I read about how much air travel (even if it's only my mangoes doing the traveling) contributes to global warming.
Part of my resistance comes from lack of knowledge. There's two feet of snow outside...nothing is in season here right now. So if I was to eat locally, what exactly would I eat? This site went a long way towards answering my questions on that subject, but for the sake of honesty I have to admit I tossed out 75% of her ideas upon reading them because they just didn't fit my family's lifestyle. But I can see myself switching from a big box store to my local grocer and freezing some of our favorite summer produce to enjoy after the snow flies to reduce our impact on the environment. What I can't see is making my kids give up their mangoes. Does that make me a bad person? Are you willing to share your opinion on this debate?