Actually, a labour theory of value was basically a "British peculiarity"  
more than the "normal" classical theory of value. From the Scholastics up to  
authors such as the Italian Davanzati or Galiani, the "normal" theory of  
value was based on the idea of utility. Smith's position was complex (the  
value of use is in fact the utility), and only with Ricardo we had a pure  
labour theory of value. But in France (Say, Bastiat, Rossi), in USA (Carey),  
in Italy (almost all!), or even in England (Senior for instance) economists  
considered the value as a matter of both rarity and utility. Therefore, the  
"subjective" theory of value of Jevons or Edgeworth was a revolution with  
respect to Ricardo, but not with respect to the great part of the classical  
economists.  
  
What was really new in Neoclassical economics was the idea of the value as  
depending on "demand function" and "supply function": the idea of price as  
the encounter between demand and supply was much older, but in neoclassical  
economics (thanks also to mathematics) the idea of "function" (of quantity  
in particular) became central for understanding value -- and related to this  
there was also the idea of "marginal utility".  
  
The real "revolution" was the Paretian one (1900), that represents a really  
new theory of values based on choices (an anticipation of Samuelson's  
revealed preferences).   
  
Luigino Bruni