The big issue regarding digital DJ'ing this year will be the marriage of Traktor to Ableton. I know the two companies are working closely with each other right now, and I would bet body parts that this is their #1 task at hand because so many traditional two-turntables DJ's are migrating to digital, but if they are used to only spinning they want that feel preserved, and I can certainly understand that.
We have accepted digital as a new frontier, so there are absolutely no turntables in the system we are currently using. I asked my collaborator if he wanted me to look into a way to incorporate a turntable software package into our system, but he is perfectly happy with the way we are using Ableton right now. I think we are using Ableton a little differently than most cats are though. Keep in mind that it's all in the mix when it's all said and done. Ableton is more akin to old-school-style multi-track mixing in a studio where you have access to as many stereo tracks as your hard drive can handle, and you fade these in and out with each other. We have entire songs loaded into the spaces where clips or loops would normally be placed, and we limit ourselves to eight columns,"tracks", or "channels" if you will. We load the bottom four or five rows with full-length completed tracks by other artists or tracks we have created in the studio. Then, above those, we have a lot of different low-register kick beats to choose from that are loops, although some are quite long being anywhere from a couple measures up to a couple minutes in length.
The remaining spaces - and there is plenty of room in a single Ableton set to render a four or five-hour-long performance-The remaining spaces contain various percussion elements, synth lines/runs, and loops, as well as pre-recorded sequences, beats, or loops of parts of entire songs.
Now - we rigged up a Logitech joystick to the laptop which allows us to "drive around" on Ableton's screen among the 144 some odd clips per set that we have loaded, and we can basically cherry-pick which clips we want to play. When we land on the single clipo we want to play next, we just pull the trigger on the thing and the clip will begin playing on the next "one" count that rolls around.
Ableton also has a great MIDI clock signal and that allows us to attach some wild external MIDI devices like say an Electribe, an MPC whatever-thousand, grooveboxes, sequencers, drum machines - There is no end to the options, so yes-while you may lose the ability to scratch, which is a bi-proiduct of the nature of how the turntable works, there are, on the other hand, thousands of hidden tricks or "moves" if you will hiding out in the built-in effects in Ableton as well as a KP3 tossed into the mix.
I can type until my fingers bleed, but actions speak louder than words, so here is just one massive example of what can be accomplished using Ableton Live:
http://www.youtube.com/watch?v=xZS1p7aAngs
