List of teachers, gurus and realizers
A comprehensive list, from which most other lists on the web derive. It provides a link to each teacher listed together with their location and a quotation from their teaching.
The Gate Keeper - A comprehensive list, alphabetically organised, of links to websites of past and present spiritual teachers of various disciplines.
Sarlo's Guru Rating Service may be of interest. There are many entries, though some of the descriptions appear to be somewhat disrespectful!
In The Light - This New Zealand site has brief biographies, pictures etc. of 'world teachers', both current and throughout history. The list is now very comprehensive indeed
Clearly views from one who is not him/herself enlightened are bound to be subjective and liable to error. Since a Sage does not discard the nature of the body-mind entity upon Realisation, a guru may exhibit all manners of idiosyncrasies. Rick Ross' site contains news articles about cults and dubious teachers, though these too must be treated with care.
Strictly Spiritual has tips for evaluating a spiritual teacher for yourself, as well as a personal ratings list.
There is a book, called 'Coming Home, An Invitation to Rediscover our True Nature' by Jan Kersschot, that includes interviews with a number of teachers. Extracts may be read at the site.
See also the book by Paula Marvelly - The Teachers of One, recommended in the Books section: UK pages or Other.
Another book, called 'The Awakening West' by Lynn Marie Lumiere has interviews with Adyashanti, Peter Fenner, Gangaji, Douglas Harding, Catherine Ingram, Kenny Johnson, Francis Lucille, Satyam Nadeen, Mira Pagal, Robert Rabbin, Byron Katie, Rolle, Isaac Shapiro, Lama Surya Das, Christopher Titmus and Eckhart Tolle. This is a newly published version of the book.