I think Traktor Pro is the new 'industry standard' virtual Dj software these days. There are others, as previously mentioned, coming up through the ranks.
Also, Ableton live seems to be the perfect target software/audience. Max4Live (M4L) is amazing and lets you create some amazing stuff.
I use a piece of software called Isadora which I often sync video too via Traktor or Ableton. Isadora can also send out DMX via a lanbox and is very powerful. If you want to know more just let me know.
http://www.troikatronix.com/isadora.html