Thank you very much for all your time and experienced advice.
In response to Grisleybutter, some of the items (e.g. Adcom) I have had for many, many years, other items were recently gifted to me and I have not had the opportunity to test them all.) I appreciate your advice on quality - and maybe selling it all for a $1,000 integrated amp. But first I am going to play, er... experiment, with what I have - as many of you suggested. After all, the Mac was recently refurbished and the speakers are like new.
Yes, GHDPrentice, I agree - I am lucky to have these options.
Thanks to all of you - your advice was helpful. Clearly I need to stay up late for some experimenting! Given the small size of the rooms in my 100+ year old house I think the Maggies are out. Radio reception is terrible where I live, so the Pioneer is out as well. Likewise, the cheap sub will be out. And the Niles, although reported as good quality, will probably be out as well since I won't be using it, and someone else might.
I am going to research phono--outs for use with the GTA into the Mac to learn how that sounds. (Thanks Russ69, I had forgotten about that option.) I might have learn about tubes next. I'm sure the single tube is pretty old. I have already paired the Adcom with the Mac, so I will see which I like better. Since the B&Ws and Totems are like new, I will keep both sets.
I'm not sure about the Super Cube 3 sub. More experimenting. The cheap one is out.
And yes - I will start saving to replace the sources - the Rega and the TT. They both have a bit of mileage.
Thank you all again!