Which small block A Body is the most sought after

Motor and trans, and hardtop (not getting into optional accesories):

Most valuable is the 71 Demon 340 4spd very closely (or a toss up) followed by the 71 Duster 340 4spd. They have a wide range appeal with graphics and high impact paint. The guys that are used to owning B and E Bodies tend to buy these as thier first A-body. That drives the price up.

Most valuable regardless of body type would be a 68 340 Dart GTS 340 4spd convertible or 68 340 Barracuda S 340 4spd convertible. Some think the Dart pulls more money. Might be a toss up.

Getting into optional accessories and dealer package cars the 71/72 GSS Supercharged 340 Demon 4spd car would be tops. If they made one/any with a folding roof that would be even more valuable and sought after. IMHO that would top the 68/69 340 convertibles. Second would be a documented Savage Barracuda.