The EFF now has a privacy tool called HTTPS Everywhere available as a Firefox add-on at https://www.eff.org/https-everywhere
This causes many pages that support https access to use https. Examples include Google, Wikipedia, and Amazon, as well as others I haven't tried, e.g., Twitter and Facebook. This seems a valiant attempt to make it harder to eavesdrop on traffic and simply like a good idea. It's in the spirit of "encrypt everything," the idea that all traffic should be encrypted simply because some people think encrypted traffic is likely to be more important, more likely to include incriminating informations, etc.
Related post: http://martesmartes.blogspot.com/2010/07/important-privacy-development-from.html
Sound track: Depeche Mode, "Love In Itself"