On Line Audio Mail Order Retailers

Besides Music Direct, I've also had great service from B&H and Audio Advisor. If you find yourself in New York it's worth a visit to B&H, a giant fantasyland of gear...audio, photo, every kind of electronics you can imagine, with a staff that knows its stuff. It's pretty much the most fun you can have in Manhattan. 

I think most of the online retailers who sell high-end stuff have people who can give you support when you need it.  It's kind of strange though - Most of these online companies charge full list for their products.  When I go to a brick and mortar that charges full list I get a demo and setup in my home.  These online guys give you none of that and still charge full list for the most part.  But to answer your question, I've had very good dealings with Audio Advisor and Music Direct.  They had people available to answer my questions about the products and were very courteous and knowledgeable about what they sold. 

I've bought stuff of all kinds from B&H since before the website, and never had a problem. The only hassle is the hours they are closed/offline. I'm not that impatient anymore, so I just wait until they reopen.

Music Direct is a pleasure to deal with. I got my Marantz separates and JBL 4319 monitors from them. If you know what you want, it makes it easier.

For car audio, Crutchfield hands down. Huge selection, superior customer service, from budget gear all the way to high end, generous return policy......always a painless experience. Never ordered home audio from them.