Mine varies based on the gig, but whenever I can bring my Gemini/DMC122, I am happy. Over 10 years use and it's just as useful now as ever.
If I have more than a couple piano tunes, I like to have an 88 key board (currently the K2700). Piano on the DMC is NO fun. I've tried introducing VI approaches to my rig (Macbook, and 2 different iPads). I keep coming to the same conclusion - for live gigs, I am a hardware guy. I just don't like working with a computer/tablet to facilitate my playing. Next, I'd like to add a dedicated monosynth like the PolyD, or something simliar.