Most of the women i've known have said they prefer big cocks but rate mine as big. Usually the thickest they've had and longer than most. One woman had a 9x7 ex (estimated because she had a dildo "about the same size") and said it really turned her on to see it rising above his waistband or bulging half way to his knee but often hurt her or couldn't get fully hard, even though her and the guy were only 18 at the time. We also played with that 9" dildo and I know, from trying, that she couldn't use the last inch. When we split, we remained friends and have talked sex since, she hunted online dating sites for a huge cock, reckons she'd love to try a fat 10+ incher but failed to find one before settling down with someone "average".
The only woman I discussed cock size with who didn't prefer large cocks reckoned she prefered "small ones like yours", that me and another similar sized guy were the only ones who could give her multiple orgasms and other guys she'd known had all been bigger!
I guess that the main thing this goes to show is that, during pillow talk, women tell you what they think you want to hear...