Welcome to the wonderfull world of Amiga which, at times is both frustrating and satisfying.
One addition to the list, as far as what you are looking for, I would mention that the A3000 is the one Amiga that has a VGA connection already built in, so any plain PC monitor will work, along with any of the Amiga specific monitors built. Plus, it has Zorro3 slots, if for some weird reason, you want to use PCI cards. With the rest of the models, using a VGA requires a scandoubler, or a videocard (RTG card), check the hardware site listed at the bottom of the Amiga.org page.
The only "downside" is that the A3000 uses the ECS chipset, so you can't play some of the "newer" games made. So the A1200 is best for that, and the A4000 is the penultimate, if you want to do serious stuff. Graphics, animations, video work, etc.
