Something like https://gpgtools.org/index.html with your own open source mail server and computer?

Right now it is a crapshoot about what is secure and what is not.  Between certificate authorities being compromised so you don't know if you are being MITMed, backdoors in MS software (and potentially Mac OS X), Blackberry, iOS, Android (plus either intentionally crippled or stupidly designed PRNGs), Tor issues, and the like, you have everything to worry about if you really need something that is secure.  

As far as a random (ha ha) web site, you don't know who is really behind it (as stated above by GreyHawk and NP some web sites in particular).  In the past you might have thought that big companies (Google, Apple, RIM, MS, IBM etc) would stand up for privacy, but in reality none of them have been doing so as of now from what has been published.  Or at worst, they've used poor security practices or allowed working groups to be derailed so that the standards can be more easily corrupted.