I am attempting to gather all of the library vendors that provide e-books. This is a preliminary list of new and established vendors. I've added some brief commentary on those that I have tried. If you know of any that should be included that I have missed, please add them in the comments and I will move it into this post.
Overdrive
The big daddy of library e-books. I've used them in libraries off and on since 2007. They are by far my favorite, have provided the best collections, and have evolved with library demand. (Examples, used to be no iPods, that changed, used to be no Kindles, that will change).
NetLibrary
I haven't used this product, but will probably establish a trial shortly.
Recorded Books One Click Digital
I haven't used this product, but will probably establish a trial shortly. Per Sharon K's observation, Recorded Books is downloadable audiobooks only.
Ingram MyILibrary
I've used the e-book and downloadable audiobooks. At the time, the e-book didn't allow transfer to devices, which is a big deal for me. My library currently subscribes to the downloadable audio and the stats have been through the roof. It beats Overdrive on the price of the service, and the audio is device agnostic. However, there are some indications that the audiobook portion of the MyILibrary may not continue.
Gale Virtual Reference Library
Will start using this service next month. Mostly Gale Encylopedias and general reference books placed on the web, downloadable as pdf (either by page, chapter, or entire book) and no Digital Rights Management on the books.
3M Cloud Library
Completely new service, I am attempting to set up a trial, but I'm sure so is everyone else. Only thing I have read about it in depth is this post, 3M's eBook Cloud Library Didn't Come Out of Nowhere. (The txr page may be what it will look like?)
Recommended by Steven Harris, Director of Collections and Acquisitions Services at University of New Mexico:
Safari Books Online
Books 24X7
EBL
Ebrary
Recommended by Steven Harris, Director of Collections and Acquisitions Services at University of New Mexico:
Safari Books Online
Books 24X7
EBL
Ebrary
Recommended by Greg Schwartz, Library Systems Manager Louisville Free Public Library:
Baker and Taylor Axis 360
That's all I have so far. I'm not including any free e-book sites like Project Gutenberg since I am looking for e-book vendors that provide new content from major publishers to libraries. Is there anything I am missing?