The question of authenticity has always been an issue with live performance from electronic musicians and it's been one of the biggest complaints of those who refuse to acknowledge the possibilities that technology provides. I recently noticed a number of videos that address this by demystifying the process and recreating the process by looping material live. Here are a few examples:
Kid Beyond hails from the hip hop side of things and this cover of Portishead's "Wandering Star" is fantastic as he creates a fairly dense soundscape only using his voice.
Venus Hum are all about synthpop and here they create the foundation for the song live and work from there.
I had previously mentioned her technique, which is what first brought this trend to my attention, but here is KT Tunstall doing her folk pop thing with a little help from a loop pedal.