Thanks to Andy Rowell for passing this one on. The German Bible Society has made available free online versions of its texts, including the NA27, the Septuagint and the Biblia Hebraica Stuttgartensia. It is a very attractive user interface, with nice unicode fonts, browsable and searchable.
German Bible Society: Online Bibles
No critical apparatus available (yet) but I'm sure it goes without saying that this is a very exciting development.