It depends on the product and store for me. I don't have anything against using chain stores. I grew up in a working class area and know lots of people who work at Walmart to pay their bills, and without it, in a small town like this, it would be even harder to find ANY job, though I realize that there are definitely better jobs and better companies. I also have paid my way through college and worked 3-4 jobs at a time to keep afloat, so price matters for me, and I don't have the class privilege to avoid Walmart at all costs.
However, if there is a choice between a chain and a local store and they cost about the same or the local store is closer, I will use the local one to help out a community person more directly. If I get a car radio from a local place rather than at Walmart, the person that installs it for me locally gets a couple hundred bucks, whereas my friend at Walmart or Best Buy or whatever would not benefit at all either way because they'll still get paid minimum wage.