STein,

You are all over the place but for what it is worth:

It beats me why ANYONE would want to buy the new PSR750.
Either go for the toprange here the 950, but MUCH better still in my view, get yourself a decent secondhand PSR910 and with the money you save you can almost buy yourself a brand new KORG PA600 in addition to that. With the PA600 combined with the PSR910 you will have a killer set up that beats virtually most of all that has been suggested so far.

JOhn

P.S. if the PA600 would be out of range due to money spent on the PSR910 you could still opt for the PA500,new or used.
I am sure Donny will be able to recommend you these keyboards....