There is a complicated formula for calculating changes in white dps as they apply to both critical strike rating and RAP.
Being a nerd, and being bored at work, I went ahead and figured it out. Really what you have is one formula, used twice to compare the changes. Please keep in mind that this is only for white dps, as the dps from your special attacks varies according to your shot rotation.
N = Net DPS
M = Mouseover DPS
C = Crit%/100
1.5 = Damage modifier (50% critical strike damage bonus. Add more if you're specced for it)
N = M x C x 1.5 + [M-(M x C)]
Just use this formula to see what you have right now, change the numbers for whatever you're gaining or losing from changing to a new piece of gear, and you will get a pretty good estimate if it's better for you or not.
Me? I chose to go with an agility/crit spec. Haven't met a damage meter I couldn't top =)
681 Agility
28.97% Crit
1681 RAP
Only buffed with AoH and Trueshot
Edited, May 1st 2007 12:53am by gbarbine