Brilliant! Welcome to the forum and your Amiga 🙂. Earlier in the year I set up an unexpanded A1200 I received so here are my recommendations:
Get a Compact Flash or SD Card to IDE adapter to use as a Hard Drive. They are silent, cheap, low powered and easy to buy media for Eg:
https://www.amigakit.com/internal-card-adapter-a1200-a600-p-12672.htmlAlso I recommend a Compact Flash to PCMCIA kit to copy downloaded files from PC or Mac easily (assuming you have one with a Compact Flash port, or a USB adapter). This made it so much easier to get files to a non-networked machine.
https://www.amigakit.com/a1200-hard-disks-c-182_24_78.htmlFor accelerator and CD it depends on what you want to use it for. I have a Blizzard 1230mk IV in the new unit and it makes it a good machine for many uses. Backing up one of Boing-ball's recommendations it's a good balance of power and compatibility. I moved to a PiStorm in my main machine and it makes it a big difference on a budget eg RTG, power for demanding games etc. I hardly use my CD ROM any more because of the other ways I have to access files.
I've only used one classic monitor, a Philips 8833 mkII. I've had it for about 25 years and is still a beautiful picture. I understand it's basically the same monitor as the 1084.
