There are many reasons to place J. Crew on the top of this list. J. Crew and Banana Republic, both clothing brands aim to be looking like a million bucks (without spending that much of course).
Both of them specialize in timeless American styles with a touch of modern design and fabric technology. AND, more importantly, both of these clothing brands use ethically sourced and environmentally-friendly materials to produce most of their products.
At this point, we would also recommend you to check out Madewell, a division of J. Crew that is known for producing seriously great denim jeans and jackets for style-conscious American women.