Go with the D9200.. it can do standard res up to VGA (640x200 @ 15KHz to 640x480 @ 31KHz). Plenty of options for hooking it up, too, as far as video cards and display modes (I do believe these come with a DB-15 connector by default). Windows will look fine on a 27" @ 640x480.
The vision pro is probably #2.. I don't know anything @ that particular monitor, but if it can't do standard res (640x200 @ 15KHz) then authenticity will be lost (then again it would be easier to plug and play with any old video card if it isn't 15KHz capable). I'd probably bet Windows will look best on this, though -- these are like low-res computer monitors (that max out at -- usually -- 1024x768.. interlaced, unfortunately).
I wouldn't recommend a medium res monitor. You'll have to use a video card that can support its specific refresh rates and display modes, and there will be no pleasure in wiring or configuring it. Besides, nobody uses medium res for their games that I know of except some Atari games like APB and Escape from the Planet of the Robot Monsters.
Oh, and you should probably look up a Happ distributor instead of buying from Happ online.. you can probably save a little bit of money.. don't remember the name, though.. American Amusement(s)..?