As far as gaming is concerned, the 5930k/5960X only make sense if you plan to go tri/quad-SLI.
For most professional software that can make use of a 8C16T CPU, the 5960X would beat the 4790k/6700k even with the 5960X at stock clock and the other two OCd' in most cases, so no contest there if you actually do something that requires that much processing power.
Um, the 5960 is clearly the better for everything with 16 threads. It will be equal for single-core processes once it is overclocked (and who doesn't overclock a $1000 processor).
As far as gaming is concerned, the 5930k/5960X only make sense if you plan to go tri/quad-SLI.
For most professional software that can make use of a 8C16T CPU, the 5960X would beat the 4790k/6700k even with the 5960X at stock clock and the other two OCd' in most cases, so no contest there if you actually do something that requires that much processing power.