The forum has been getting spammed with questions like this in the past week, for all three specs. I guess we could get some psuedo-official stat weights put together to list in the OP, but I dunno what's worse: the spam, or everyone following a list of weights blindly without understanding why.
Short story, whoever looted that crit/haste ring to you made a mistake. You'll replace it the instant you get any 670 ring with BA on it (eg. the
BA/mastery ring from the same boss), and haste is still terrible for us. It should have gone to a DPS who could get full benefit out of it, and then you wouldn't be asking this question. Hang onto it for your WW offspec I guess, but in the meantime my guess (without looking at the particular numbers) is that the BA on the 640 is going to beat out the extra agi+stam on the 670.
Run some sims if you want to be sure.