Originally Posted by Dorvan

Check out either Redcape's spreadsheet or Rawr, both will give you relative weightings of the various DPS stats available to you. If you want to know the minute details you can examine the actual formulas within the spreadsheet/code which produce those weights, but the high level summary is that when you sum up for each stat the dps contribution coefficients for each ability, strength handily beats expertise for any realistic gearing level found in WotLK.