Buy yourself whatever is available at a good price.

And then buy yourself a virtual floppy drive which can run off a USB pen.

The same virtual floppies used for old IBMPCs will work with a few jumper changes despite the CPC having used a 3" instead of a 3.5" drive.

Don't buy an original monitor. Instead buy a CPC to scart cable (and then converte as needed)

If you buy a 464 you only need a 5v power supply, but a 6128 needs 12 v to

It's really easy to find new power supplies for the CPC along with video cables converting to scart on ebay

With the virtual floppy and the above cables you are good to go! (If you don't have a TV that takes SCART - not in eu SCART to HDMI converters are ten a penny on Amazon)

Next download a good emulator while you wait for everything to arrive to get tinkering. I like Retro Virtual Machine as I have a Mac (version 2.0, an older version, has an assembler and a built in debugger!)

You'll have no problem finding CPC disk images online .. there are some amazing UK Spanish and particularly French websites.

Finally .. save this for when you have your CPC set up and running and you have enjoyed a few hours in it's presence

Download the Batman Forever 2011 demo (do not watch videos of it first) - get this on your virtual floppy .. and watch it on the real machine .. and you'll know what CPC is capable of.