Not sure if this fits since some of the characters aren't furries (it's about 50/50 so far), but I think Forest Keep is a pretty good one:

http://forestkeep.net/

It's a work in progress, and it hasn't been published as an actual book yet. Chapters 1-47 are available for download from the archive as a PDF file, chapter 48 is on the Current Chapter page, and 49 and 50 (as well as all the previous ones) are posted on FA and sofurry.com under the username "shimrod".

There are a few sex scenes, but they're presented in a tasteful manner (in my opinion). Also, while some of those scenes (particularly the first ones for the various couples) are vital to the plot, they aren't the main focus of the story. Instead, it mainly revolves around the romance between the couples and the resulting clash of cultures/species.

>>1301
PS: aside from the fan art, there aren't any illustrations

Forests of the night, or any of the four books related to the Moreau series by S. Andrew Swann. its mroe furry than it has right to be and features a fair bit of implied and lightly explore human/furry furry/furry love making. a good series that never got more attention. Nohar remains a favorite for furry characters.

http://en.wikipedia.org/wiki/Forests_of_the_Night

I personally like most of the Redwall series, just because of its dialogue. And that's regardless of the furries in it.

http://crash.ihug.co.nz/~howellg/stories/stories.html

I have read most of this books here The Human Memoirs, Light on Shattered Water, Storms Over Open Fields, Lies in Red Leaves. they are very good books, and you can download it to your computer as well free. there are a bunch of furry books on amazon as well now, even some for kindle.