Been a while.....

[CSixx]

You certainly won't get as much money selling as a lot rather than piece by piece.

I think the biggest questions is; will you come back later and try to reacquire things?
Based on the example in your sig, it will cost you significant time and money to repurchase them if you do decide to come back.

[CSixx]

Questions only you can answer unfortunately.
I, personally, will always keep at least one classic Amiga machine.

Your a1200 should fetch a good price.

You could always run an emulator on your main computer to get your "Amiga fix".
Or even explore some newer options if you decide to get a dedicated system again. (AROS, MorphOS, OS4 systems, Natami, Minimig)