Perceptions of beauty have changed throughout time. For example, in the times of the Talmud, R' Yochanan, who was described as being fat (Berachos 13b), is also described in the Talmud as being exceedingly beautiful (Berachos 20a, for example). However, today obesity is generally considered to be unattractive.
Similarly, across different cultures beauty manifests differently (See this slideshow for some examples - disclaimer: contains photos which I did not peruse to verify modesty).
What I am wondering is if the people who are described in the Torah as beautiful (Bereishis 29:17, for example) were beautiful according to their time and their culture, or if there was an objective nature to their beauty which was not subject to vicissitudes of time and place.