While the economically compromised neighborhoods of South Dallas are the hardest hit by crime, visitors should take care in all areas as one would in any large city in the United States with a population over one million.  Central Dallas is a target area since it is also the area that many tourist attractions are located as well as the Arts District and the nightclub districts of Deep Ellum and the West End.  Deep Ellum has sort of gone downhill in the last few years.  Try McKinney Ave near Lemmon for better nightlife, without the crime of Deep Ellum and the West End.  On Lower Greenville Ave, pay the extra few bucks for a parking spot in a designated lot.  The wreckers are lightning quick and merciless.