I love Nashville. I'm usually in town once or twice a year hanging with friends, playing, and buying cool gear.
Guitar Stores:
Rock Block - The best around for pedals... They have a few guitars, quite a few amps. I easily drop 1k every time I'm in there on pedals. I'm a pedal guy and they have 'em all.
Carter Vintage - A place that is super cool. A good selection of everything old and new - guitars, amps, and pedals. I bought an old guitar from them and was very pleased. Definitely better than Gruhn's IMHO. Gruhn's is not as welcoming IMO.
Gruhn's - Again, not my fav but you have to go at least once. He's got primo stuff in there.
World Music - Great shop with cool gear.
2nd Gear - Used music shop owned by the biggest session guy in town, Tom Bukovac. Haven't been in there yet but will be next time. Last time I was in town they were closed. Tom's a great guy though.
Corner Music - I haven't had much experience with them but the one time I went in it was a cool place.
Guitar Center - the platinum room is the second biggest, the biggest being LA. Great selection of vintage and new high end gear. Bought an old Fender Tweed Deluxe in there a few years ago on my first trip to Nashville.
Entertainment:
Robert's Western World - Probably my favorite place on Broadway. Honky-tonk with good food and traditional country music. I'm a shy introvert with fear of crowds (unless I'm onstage, then it goes away - confidence thing I guess) and Robert's is a calmer crowd than Tootsies and some of the other places. Love their grilled cheese and burgers and hot dogs. Great food and drinks, and my favorite bar band in the world - The Don Kelley Band featuring Daniel Donato - a smokin' player I'm proud to have met and befriended.
Tootsie's - Definitely one of the hottest clubs on Broadway. Slightly more modern music than RWW, which I dig too in addition to the music at Robert's.
The Stage - another honky tonk that has good music.
3rd and Lindsley - Great place to catch big name artists and session players playing live like Brent Mason and the Players, Tom Bukovac, Vince Gill and the Time Jumpers, etc.
The Family Wash - Great place with good music more set up in a restaurant setting than a bar/club setting. Be sure to catch Sons of Zevon with Audley Freed. He often brings in other Nashville cats to play classic rock covers.
Food:
Tough for me to help in this category as I don't like sitting in restaurants, especially noisy ones unless it's music. I also do not do formal dining, so keep that in mind. I normally eat in my hotel.
Wildhorse Saloon - Normally I avoid these types of places but was recommended to go and did once. Great food and great entertainment. Although it was a bit crowded and "high energy" for this tame guy. But great place nonetheless.
Elliston Place Soda Shop - An awesome little retro diner with good food and killer ice cream and milkshakes! Typical diner type food - sandwiches, burgers, fries, etc. But killer ice cream and jukeboxes on every table. Also, it's right next to Rock Block!