The Inner Woman: The United States Preventive Services Task Force, the arbiter of evidence based medicine, has cogitated on hormone replacement therapy and made the results public. Estrogen is a no-no for preventing heart disease and osteoporosis, and not worth its risks. They didn’t consider estrogen as a treatment for menopausal symptoms, though. The worthiness of that remains up to the patient:

For an individual woman, the balance of benefits and harms may vary. Women considering taking HRT for prevention should make that decision with their clinician in the context of a discussion of benefits and harms of HRT and alternatives to HRT for the prevention of chronic diseases.

I'd say they struck a pretty good balance, although I disagree with the stance on osteoporosis. A lot of people have begun pushing other, newer drugs for preventing osteoporosis in light of the recent brouhaha over estrogen, but the truth is that those drugs simply haven't been studied and scrutinized as much as estrogen. We can't say with any confidence that they're safer. Still, the decision to take a drug to prevent a possible future illness is something that should be left up to the patient, and should be done with full knowledge of its risks, and how much or how little we know about those risks.