Fran is right about the "visual issue".
Listeners already think that everything is pre programmed, so if they see a pc on stage it's a lock that they will assume it's "KARAOKE TIME" (yuk)
Whatever you do - don't ever let the audience think that you are just playing along..... even if you do sometimes. It's vital that the crowd respect you as an entertainer, and not just a "jocky".....
disk or otherwise !
PC's have been a mixed blessing for the entertainment industry and it's tough to decide whether or not to use one on stage. Think of this:
Most of your listeners HAVE a pc at home, and LOTS of people are familiar with midi files and MP3 files. Many people will assume that you are just "following the leader" (pc)
In support of the pc:
LOTS of people are used to the sound of a big, produced arrangement that is "note for note" like the recordings. The sequenced material will usually go over very well, if you put some human element into the performance. (vocal, solos, etc...)
In summary - it's dangerous to be SO automated in your show because it shrinks the playing field. Being a performer is a dream for many - don't let the crowd think that they can do what we do just because they bought a computer. It's not that simple.
If you DO use a laptop on stage, be sure that you don't keep your eyes buried in the screen. That's a sure-fire give a way that you are reading words, and then all the "K" singers come out of the woodwork.
"Do you HAVE..........."
(what a nightmare)