my minimal required gear nowadays is a notebook, an interface, a midi controller and a mouse.
I did my first liveset just with hardware - Electribe MX, DSI Evolver, Jomox M-Resonator, little Soundcraft mixer. But I wasn`t very pleased with the results. I couldn`t apply any properly mixing (but this seemed to be a problem for me just at the end - at first I liked that "rough" sound straight from the synths). Then I realized that this liveset isn`t sounding anything similar to my produced tracks. Because when working on hardware with just two hands you can`t do all the tricks you can achieve on your productions. I don`t say A is better than B, I just mean that my liveset didn`t fit to my productions. And I wanted it to fit =)
On my next liveset I switched to software (Notebook, NI Maschine, two midi controllers). But I was doing more or less exactly the same. I couldn`t apply a lot of mixing because 10 entities of Maschine loaded into Ableton Live was something like 90% CPU usage. Workflow anyway was pretty similar to my hardware liveset.
Nowadays I am using Ableton Live as my sequencer. The newest liveset consists of 8 tracks which I have produced previously in Live. I don`t arrange a whole song, I just produce audio clips in Live-View. Some parts are for peaktimes, some for breaks. Then I mix (mixdown) the audio clips and copy the mixed wav-files into the liveset-project. I do a rough buildup of my liveset - which doesn`t mean that I pre-produce the whole liveset, I just arrange something like "markers" which tell me where to go over the time. Between those "markers" I am arranging the several clips improvised, individually and on the fly during the gig.
I know that this way isn`t a REAL liveset. Neither my "improvisation" is a real impro because I am arranging pre-produced loops improvisational =) But anyway, I do have a lot of moments in my liveset where it depends on my manual gearcraft if something goes well or wrong and I have to tweak the knobs all the time too
On the other side I am doing live ambient impro sessions with a good friend. guitars, synths, notebooks, controllers. Nothing is prepared, we never know in which direction it will flow. Did some gigs with that project and people where asking "Are you serious? When is this noise over? Is that just a intro for a drumnbass tune?" and things like that. So, when I do techno livesets I want the people to dance and have fun - and I wanna dance and have fun too. So my real impro liveset stays ambient