The new Gemini CDT-05 is both a CD and vinyl turntable with cue points, token effects to play with and a superb CD scratch sound. It's a space-saving innovation.
Mixvibes DVS is an economical way of gaining vinyl control over digital files as it will work with any soundcard combination.
Visiosinic's PCDJ Scratch made a modest attempt at adding scratch control to the popular DJ software. It can be a bit tricky to set up, but it's quite cheap.
The Alcatech Digiscratch 2 offers advanced mixing controls, such as sampling, looping, and flexible interface schemes.
The scratch DJs favourite, Rane's Serato Scratch Live is the best sounding scratch for turntablists. The only downfall is that it doesn't have many features.
The original innovator in this dimension, FinalScratch 2 implements a high quality interface with Midi, soundcard, Mic and Aux inputs, plus an advanced application.
Arkaoss VJ works on Mac and PC, has an intuitive and easy to use interface with loads of features. Looks a bit dated these days and is quite pricey.
One for the really advanced VJ who wants to get their hands dirty, Modul8 has ten-layer mixing, Alpha channel support and 3D wizardry. It's a very innovative option.
Resolume is a versatile application suited to beginners and professionals, with unlimited effect plugins, sensible organisation and is loads of fun to play with.
The only proper AV solution comes from Camart. VJamm 3 allows DJs to synchronise video clips with BPM and play clips just like a sampler. Coldcut's favourite!