If you want live mixing then Traktor with a VCI100 interface is cool but a bit of a fiddle to work with. You'll need a very good sound card and fast computer to avoid latency.
Cant go wrong with vdj to be honest i use it but like was mentioned earlier it may feel like cheating....
i dont know why alot of djs see it as cheating as it aint much different from most cdjs now so....?