In fact, I'm here now for my wife's family Christmas. Can't believe this route hasn't been mentioned:
82 to Tuscaloosa/ take bypass of course, to Birmingham/ hit 65N all the way up to Nashville.
I go from Starkville, but I always start clocking my trip from Columbus (4hrs)
From Columbus: 1 hr to Tuscaloosa toll bridge / 1 hr to 65 split in Birmingham / 2 hrs straight up 65N = 4 hrs
Very pleasant trip and before u know it, ur rolling up thru Cool Springs (outskirts) 20 mins before your ETA.
*tip- exit 282 in Warrior, AL is the halfway mark. Excellent place(s) to top off ur gas and eat (McD's, little caesars, hardees, taco hell, pizza hut).
Best way by far.... Happy Motoring, dogs!