Good old 2ch versus multi-ch, what to do?

Betat only YOU can decide.
These forums are great for advice but they work better for filling in gaps rather than a cast in stone recommendation.
Try to demo a good CD player and SACD player in your system.
For what it's worth I came to the very conclusion you suggest in your last post-buying the very same player you mention.
Using both advice from Audiogon members and home demo's and my own logic I decided against investing further in SACD-I still have a SACD/DVD player in my system.
However there is a pro-SACD group also who haven't replied to this thread.
You might well find the positive things in SACD that I didn't and others do.
A quick search on SACD will show various debates-however sadly Audiogon decide to delete some threads for reasons best known to themselves meaning that you endlessly end up making the same points in an effort to help people.
Freezing threads that have run their course would mean no more input (if they are considered contentious)but having them in the archives would serve many purposes.

With regards the well mentioned Sony XA777ES this is the very machine I considered.
By listening to a well respected Audiogon member and SACD advocat he told me that the Sony was behind the Linn Ikemi on CD replay-well in my system the Ayre CX-7 destroyed the Linn.
From this point of view there was no contest for me.
As regards multi-channel I've heard some impressive stuff but it's not for me.
This has all been discussed before and I return to my previous point why Audiogon should choose to delete certain threads.
The result is myself and others are repeating the same points and personal experience.