There are only two high end stores. The better one is Nicholson's (ask for Tom Berry or Larry Staples), they usually have a pair of Pipedreams set up. The other is Audio Video Environments. The last I checked they were more heavily in to the home theater side of things.
For used CDs try Phonolux on Nolensville Pike. They have the largest selection including a lot of new releases that I assume they get from people in the music business because they have a lot of promo copies. I just got a sealed copy of Bob Dylan's latest for $10. Beware of the vinyl though because they have an "all sales are final" policy and they charge a premium price. If it's scratched or noisy, you're stuck.
CD Warehouse near Vanderbilt on 21st Avenue also has a good selection. Not to be confused with the similarly spelled national chain that bought Blockbuster music. A few blocks further down on 21st Ave is The Great Escape. A good source for used CD's but you have to be very careful with the vinyl. They have a lot but many are marginal quality.
