I bought five cd's from the above place last night. Next to Amazon, it will probably be one of my new favorites. I usually buy the, "like new" used CD's and have had great luck in them being in flawless condition.
Acoustic Sounds is ok when looking for stuff that is hard to find. But usually Amazon will have it too. Just have to compare prices as Acoustic can be high priced at times....as can Amazon with some things. Key is to shop around, find what you want for the best price and best shipping costs (free shipping with Amazon if you are not in a hurry).
Tower has free shipping on orders over $20.
CD Universe also has nice selection of both music and DVD's.
And for music only, YourMusic.com has most albums for $5.99 w/free shipping. Not the greatest selection by any means, mostly latest greatest stuff, and a few SACD's.
Recently I have purchased quite a few DVD's from an ebay seller including the Doobie Brothers, Earth Wind & Fire and Styx among others. He carries a wide variety of artists with fair prices and quick shipping.