These days I avoid Amazon where possible since so often it's just cheap Chinese knockoffs or obviously returned products sold as new. B&H has been a godsend for tech, especially since there's no tax with their card. Crutchfield/Headphones.com has been great for speaker and audio gear. West Elm has a consistently premium quality for kitchen, home, and furniture items (though furniture is a story of its own, with even…
I would also add rtings.com; they do a great job of documenting their process and the results themselves from their reviews with incredible detail.