Titmouse - A lot of teen and first time stories.  The sex is believable and hot.

Father Ignatius - His stories have a great sense of place.  Stories with humor, literary allusions and historical asides.

OneIdleHand - Wife stories.  All his stories feature the same characters, Steven and his wife Hayley.  They are well written, imaginative treatments of the usual plotlines.

Bitbard - This is a collection of stories from writers who I believe are all retired, including Bitbard himself.  The only common thread here is that the writers each have a distinctive literary style.

Foxbat - Foxbat writes NC stories, usually about women in their teens or early 20s.  NC is not usually my preference, but he does it better than most.  I like the story My Megan.

VulgarArgot - Vulgar Argot writes mostly long form stories with lots of character development.  The enjoyment derives from the lead up to the sex rather than from a detailed description of the sex scene itself.  He likes stories about D/s with romance instead of S&M.

TonyTony3 - Wife stories.  I don't know of an on-line source of his stories.  Try searching Google Groups.

Rachel Taylor - A few nice stories about wifely infidelity written from the feminine point of view.