Well, since my name is mentioned in this thread I might as well add my $ 0.02 to the discussion.

First of all: Everything changes. So does music and the musical taste. When Sinatra, Davis Jr, Amstrong etc. where performing they did so with a bigband with up to, what, 25 musicians. That was live.

Now some clever guy invented the synthesizer and all of a sudden the horn section and the strings could stay home for the gig. We now have a band with a drummer, bass player, one or two guitar players and a keyboard player. No horns and no strings on stage but they are audible. Are we still live talking live performance? Most will say this is live. OK

I also play in a 5 piece band: drums, bass, guitars, keys and vocals. I sing, play guitar and do two songs on keys. Our keyboard player also plays guitar and does backing vocals. We used to have a drummer who could sing very good, so he did the lead vocals for several songs and backing vocals for the rest. Still live performance, agreed?

But then the drummer decided to leave the band to do a metal-project. We found a new drummer, but this one does not sing (luckily ). So I decided to buy a TC Helicon VoiceLive 2. This vocal processor among other things generates harmonies based on the lead vocals and the input of the key set, midi commands or music. So now we have strings, horns and vocals from a box. Are we still live?

OK, we're invited to a wedding. The band that's playing consists of o drummer, a keyboard player and a lady singer. We hear a bass guitar, rythm guitar, horns, strings: the works. The keyboard player has a very nice keyboard and uses sequencing. Is this a live performance?

I earn most of my living doing solo gigs. I have some $20K worth of equipment with me: sound and lights that most of the times I set-up, operate during the gig and take down myself. The usual gig lasts about 4 hours (with three 15 min breaks). I sing to professional backing tracks. The venues book me to entertain the audience, make them sing, dance, feel good and above all: make them thirsty. I and I alone am responsible for the gig and for the mood of the evening. I have to give 100% of myself every moment of that night; there is no-one to take a solo and thus the attention of the audience. I cannot use a guitar or a keyboard as a shield. It is just me and my microphone. Most of the times I don't even have a stage or a riser so I have to do a dynamite presentation to be noticed at all. It is fricking hard work. But is it a live performance? I think it is. It is me singing, improvising and reacting to the audience.

Is it karaoke? No. Karaoke is when backing tracks are played and the lyrics appear on a screen. People from the audience take the microphone and sing one or a couple of songs.
Is it a live performance in your opinion or is it something you would enjoy on your night out? That is up to yourself.

I do like playing with the band better and it sure as heck is a lot easier performing with the band standing behind me. But when I drive home after a succesful solo gig and I have made the crowd gone wild all on my own.....yes, it makes me feel good. That and the pay is a lot better on solo gigs.... A man's gotto eat you know.