So I was looking at the Soul Drinker prestige class, and one of it's abilities is:
Energy Drain (Su)
At 2nd level, a souldrinker gains the energy drain ability. By making a touch attack as a standard action, she bestows one negative level on the target (two levels on a critical hit). The souldrinker gains 5 temporary hit points for each negative level she bestows on an opponent. These temporary hit points last for a maximum of 1 hour. The DC to remove this negative level is 10 + the souldrinker’s class level + her spellcaster ability modifier. At 6th level, this touch attack bestows two negative levels (four on a critical hit).
Now, the Conductive weapon property says you can apply one of your supernatural abilities through a weapon on a successful hit, but you get the option after you already hit; if I crit, and then chose to apply Energy Drain, would the Energy Drain count as a crit?
RAW, the weapon damage would crit, the class ability wouldn't, there is no clause for the ability to crit through the weapon and the weapon is still doing its normal (crit in this case) damage. The SU ability is being applied by an exception/special rule, it isn't being rolled on the attack and cannot crit.