Native Instruments Traktor, still love it for having access to a huge percentage of my catalog at once - but CDJs have made DJing fun again.
I own and prefer to perform on both Xone and DJM900NXS mixers - have always been loyal to the Pioneer series - and still am (unless you have a rotary Bozak lying around).
In the studio, Logic faded away for me about 3 years ago - am fully producing on Ableton now. Love the workflow - great app overall, they have really changed the game (unless you are a FLoops guy, then I get it - Sony ACID was a major pioneer in the category).
Mac? PC? Yes on both. Monitors? I'm a dynaudio loyalist.