On a personal level I don't see how a bike with either a threadless steerer or STI/Ergo shifters can be retro so that excludes the Klein and Specialized. Out the others it's a tough choice between the Hetchins and the Raleigh. I've always liked that Panasonic livery but the bonkers rear triangle of the Hetchins wins in the end.
if you go by the <1997 age category in the mtb forum then both sti/ergo and threadless steerers cut it as 'retro'.
Not sure what the periods are with road bikes though - they have been around sooooo much longer than mtb's.
Where does 'antique' turn to 'classic' is this the same as 'retro'? And when do you enter the no mans land up to being 'modern'?
Touche, the Klein also isn't threadless as in the modern interpretation. It has a 1 1/16th inch steerer and a special collet system developed by klein but they stopped making about 13 years ago.
But I understand the doesn't fit the retro image sentiment which is why I knew it wouldn't win here.