The Bookshelf

Texts:

Sir Thomas Browne's Religio Medici
Christopher Marlowe's Doctor Faustus (From The Perseus Project)
Edmond Rostand, Cyrano de Bergerac (In French, on the server of la Bibliothèque Universelle)
Shakespeare's sonnets (Full commentaries, pictures, and related contemporary texts)
Anglo-Saxons.net (Includes Old English and Old Norse texts, translations, and notes)
British Poetry 1780-1910: a Hypertext Archive of Scholarly Editions
Luminarium.org (Medieval, Renaissance, and 17th century texts)
Poets' Corner (Lots of English verse)
Renascence Editions (Works printed in English between 1477 and 1799)
Representative Poetry Online (More verse, based at University of Toronto, with very full bibliographies)

Dante (The Princeton Dante project. Stunning. Texts, translations, illustrations, annotations, recordings...)
Jane Austen
Willa Cather
Robertson Davies
Guy Gavriel Kay (An official site, with input from GGK)
Terry Pratchett (Includes copious annotations on the references, allusions, parodies and in-jokes)
Carl Sagan (The Planetary Society page, with various links; check out also a RealAudio interview with Carl from 1996)
Dorothy L. Sayers (DLS Society)