This is probably what you want:
http://www.theromwiki.com/Attributes
Bonus's from Stats are relative to class. Ex Warrior gets the most bonus from Strength, Priest and Mage get the least. So each class has a stat that benefits them the most.
Generally Rogue, Scout, Warrior, Warden and Knight are physical attack classes, while Mage, Priest and Druid are magical attack. There are a few skills/elites or general skills from your secondary class that cross that line and so get seldom used. (I.e. if you stat for p. att, your m.att dependent skills drop out of use.)
I think there are still a few undocumented alterations, like a Dex modifying on some Scout skills like Shot and Wind Arrows, but I believe that list is up to date.
