1- Restoration Hardware - What can I say about Restoration? They are doing things right with true attention to detail and pieces of amazing character. Their bath fixtures are works of art at half the price of Waterworks and their reclaimed wood furniture has all the charm of custom pieces. If you find their running lines pricey, just wait for the sales as they often move out inventory regularly throughout the year.
2- Room and Board - Although they don't have many stores, Room and Board pays great attention to quality and timeless design. They sell everything from Nelson lamps to Eames furniture and have the best values in sofas that I have seen. They can custom upholster to your specifications and the prices are very reasonable. I have personally owned several of their pieces and have never been disappointed.
3- FLOR - Need to change a room in a hurry? Use paint and FLOR tiles and the transformation is complete. FLOR has the most incredible range of carpet tiles that are easy to install and can be customized in an endless amount of combinations. They have tiles ranging from graphic prints (such as Union Jacks and cowhides) to subtle textures to Cable Knit Sweaters. They also have area rug kits pre-configured in tonal ranges. Overall, they are a great value and the installation is a breeze.
4- Mitchell Gold Bob Williams - If you have ever seen 'The Good Wife' on TV, you know that Alicia Flourick has some pretty good taste in decor. What you might not know is that most of her apartment comes from MGBW. The company has a wide range of styles and price points most of which are focused on gracious entertaining and family living. I particularly like their upholstered items including beds and side chairs. Definitely worth a look.
Although I would never advise that you furnish your home all from a single source, I certainly encourage you to mix and match from reputable companies such as these. We constantly are referring to these outlets as part of our Room Service package which creates custom designs for clients using off the shelf products (www.yourroomservice.com).
Let me know what you think of these stores as well as any others that might be on your favorites list!