One of my favorites has always been The Big Bang. Its a dueling pianos bar right on broadway. Its somewhat easy to miss though, you have to look up, its not street level!
If you're really into country music and all the "famous" places that Nashville's known for, you'll want to stay around Broadway or 2nd Ave. Tootsies, The Stage, Wildhorse, Coyote Ugly, Cadillac Ranch, BB Kings etc are all on there. There is no shortage of bars and live music places to walk in and out of! The street is packed with them and depending on the time of year this area of town can be pretty crowded. You may or may not have to wait in lines to get in places.
If you want to avoid the area that is more tourist heavy and is typically more local, then the bars near music row/the gulch are good areas of town (west nashville). Tin Roof is a good one. Exit In is popular. Dan McGunniess is a good pub type place. Cafe CoCo can sometimes have a cool atmosphere but its more of Vandy students, and not necessarily a good bachelorette party place.
The 5 Spot is good for live music, but its out more in the east nashville area. Not necessarily the area of town tourists may want to go exploring through...
