Re: Live Sound question
I don't think you will notice a difference in sound quality. I would do as DrumEatDrum said, though, and split the stereo signal left and right just in case, even if you don't really care about using both sides. I might be off here (I'm not an audio expert), but I think if you do that you lessen the risk of getting conflicting R and L signals (like if you're using certain effects, or if certain sounds have elements that are normally panned right and left). You can certainly use midi, an interface, and a laptop, but then you're depending on a lot more gear (and your computer will inevitably freeze up or slow down, or randomly start having latency problems). I think you're better off just using the headphone jack unless you really need to use the computer for something your keyboard can't do.