East Tennessee born and raised, lived in Memphis for a few years in my mid-20s after graduating from UT, and now live in Nashville in my early 30s. I don't want to move away from Nashville ever, but if I had to choose between Memphis and Knoxville, I would have a hard time making up my mind. I truly enjoyed my time in Memphis, and while there are problems there to be sure, for the most part they are the city's own, and don't degrade other parts of Tennessee, as many in this thread seem to think.
For all of it's negatives, Memphis offers unique cultural and historical opportunities, the state's highest ranked company in the Fortune 500, St. Jude, an NBA team, among other things. I'm glad Memphis is a part of Tennessee.
JMO.