I love these Urban areas with eclectic older homes. You are right, driving around some of these areas can make you wonder. One of the most important things to look at is what is going on in the neighborhood? Do you have investors coming in making the homes shine and new home owners taking pride in their homes? On going transition in neighborhoods is a great thing! Think equity ;)
The area you mentioned is a very desired area in Nashville. Very close to the best places to dine in town, Vanderbilt, Green Hills and downtown.
Bars are just like having an ADT system and some of these bars were the ADT system when these older homes were built. ;) Crime can happen anywhere- Living in the urban areas or in the suburbs.
There are many websites to check crime statistics. I like http://www.crimereports.com
Hope that helps!