First of all I would like to thank everyone for their comments and I hope more people will join in.
It is quite confusing, but it seems that the quality of sound should be the first concern. Flexibility second and lastly the convience of setup. Of course, the money issue is a determining factor in all of the above. Which brings me to my second question; What would the cost of the various performance techiques be i.e. how much is a good mini disc., cd player, etc.
I should add that I am presently running a PSR9000, thru a Mackie mixer with SR450 powered speakers and Mackie subwoofers. I also have a Motif Keyboard that I have not started gigging with yet, but it could be brought into the mix.

Thanks again for all of your comments and I'm looking forward to hearing more of your advice.