I'd say the A2000 is best for this guy.
It gives him many more options at a much smaller price
than either the A1200 or the A500.
I doubt that. The A2000 itself is not cheaper than an A500 or A1200, and expansions like accelerators or SCSI controllers are in the same price range as A1200 ones, or even more expensive.
And if you want to store your Amiga in a cupboard, only to take it out and connect it to a TV everytime you want to play a game, then the A2000 isn't your Amiga either.
Mind you, I really like the A2000 (I like all Amigas for that matter), but it's hardly a games machine.