Where do you buy good CD recordings?

What are the recommended web sites for buying CD’s? I noticed that some sites (like www.hdtracks.com) provide music to download (AIFF Format). What is your experience in downloading music? I like the www.referencerecordings.com web site and am looking for other similar sources. Are there any stores that you recommend for buying music? I am interesting in looking at a list of CD’s to include a brief description and some sample songs to listen to before I make a purchase.
Amazon is my #1 place for buying CD's, both new and used.

I buy at amazon.com or tower.com. Amazon has better website with reviews and I always had very good luck with Amazon Marketplace - used and new.
Chesky Records
Another vote for Amazon music.com very good selection of most types of music, reviews, the ability to sample on site and very reasonable pricing new or used.
Amazon, chesky, marecordings, & berkshirerecordoutlet (great price's but no soundclips at this one)
I am sensitive to the fact that some people on this site look down their noses at eBay, but I have purchased more than 1000 CDs from eBay over the past 10 years and have experienced only one problem; and even then my money was refunded. Moreover, many of the sellers are wholesalers and frankly have no idea of the real value of some the recordings they are offering meaning that occasional ridiculous bargains do surface as in 50%+ lower than the identical used item on Amazon which is indeed a highly reputable site. Finally, it is not that unusual to find extremely rare O-O-P recordings that are no longer available elsewhere. A caveat: I prefer easy and non-contentious transactions and thus almost always purchase from sellers with 100% perfect feedback based on a minimum of 100 successful transactions; I always pay with PayPal or a credit card which insures that ready recourse is available should a problem arise; and I do maintain a list of favored reliable and honest sellers with whom I have done much business in the past.
In addition to Amazon, Berkshire, and Tower:

the rest is from local NYC stores such as 'Other Music'

Good CD recording is defined IMO by the artist and album you like to listen to.
I use itumes (preview) to hear whether I like the music, and use the options of "Buyers used similar music" to find similar music. Then buy new CD's at amazon.co.uk which is very cheap at the moment.
I also use Ebay, but the wholesellers tend to use bubble envelopes which is insufficient protection for International shipment, shipping carton protect much better.
Favorite record companies are Telarc, Chesky, Verve but Chesky seems to boost the recordings
CDUniverse is also quite good.
The above was great information. I looked at Amazon.com and it looks good. Thanks to everyone for responding. Audiogon is an outstanding resource for getting useful info.
My favorite in NY: