My DH originally bought me a Sony ereader. That was an expensive mistake. And Sony was no help. We could not have a pdf on there at the same time as an epub. It's now a paper weight - spent about $300 on that piece of junk. A year later DH bought me a Nook Color and I absolutely love it. Can listen to audio books and also watch Netflix or even check email (although this function is slow). Barnes and Noble has a lot of free books and also authors will sometimes run a special on some of their books for a limited time. The very best feature of the ereader is being able to increase font size - the older I get the harder it is to read small print. And, since it's backlit, whenever DH and I travel and I can't sleep, I can read in bed without disturbing him.
My favorite authors are Jayne Ann Krents/Jayne Castle/Amanda Quick, Nora Robers/J.D. Robb, Linda Howard, Janet Evanovich, Christine Feehan, Robyn Carr, Carla Neggars, Janet Chapman, Sandra Brown, Susan Mallery, Linda Lael Miller, Christina Dodd, Anne McCaffrey, J. K. Rowling, Judi McCoy (dogwalker mysteries).