Whether you’re buying, gifting, or expecting an eReader this holiday season, the market’s changed a lot from last year and the year before that. Here’s a complete buyer’s guide, starting with the basics and working through the latest trends, says Yahoo! News. Kindle, Nook, or … ? What exactly an “eReader” is, to you, might depend on where you first saw them. Barnes and Noble is pushing its Nook line [1] pretty hard through its retail stores, while the Kindle [2] takes over the front page of Amazon.com every time a new model comes out. There are other eReader devices, though. Kobo [3] sells a line of basic but dependable black-and-white eReaders, which have tons of fans of their own, and a color version’s on its way. Other companies, like Sony, have their own lines; and there are eReader apps for PCs, smartphones, and tablets, which tie into your Kindle, Nook or Kobo device and can even save your place in a book…