Hey Curtis,
"The Story of O" and "The Image" are Classics - I guess I may be getting myself into trouble here by using that label again but...the three titles I cited as being Classics to me are because of their style of writing. Classic is certainly not meant as a label for something old - as for example "House of Pain" was written in 1996! Its described as scorched earth erotica which it certainly is! But it owes a hell of a lot to De Sade - thankfully though it's written with way more style! Try and find it - wonderfully depraved!!! "Cult of Pain" is a "Lessons" in a Victorian whipping club type thing with fanciful names for the participants - you'll see what I mean if you find it - Miss Skintear etc. Supposedly from 1904 - totally cold and matter of fact. "Castle of communion" - superb stuff from 1969.
So are there any other titles you've rated highly? Anne Rice has never really done it for me - I found the Beauty trilogy got boring after the first book.
All of the above are what you'd call mainstream I suppose - going a little more underground what about Victor Bruno? He wrote numerous titles and had a good eye for humiliation.
Particular favourites of mine are the "Erica" books by Rex Catt Saviour. Fantastically horny!
Totally mainstream what about J G Ballard - Crash - I know it's not what you'd describe as "normal" SM *grins* but its a great book.
Just to redress the balance a little - for FDOM you can't beat Angela Pearson(Greta X) - her "Whips Incorporated" has to be one of the best books in that genre - tho no doubt some of you may disagree? lol