Michael Green is now located in "Nashvul". Don't know the address, etc... but you might want to look up their website, snag their number and see how receptive they would be to a "drop by" while you're in the area. Sean
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.