Thinning The Field
First off the list are the Barnes & Noble e-readers. The NOOK Simple Touch is a compact device with excellent battery life and a nice display. Unfortunately, that display is only six inches in size. The NOOK Color on the other hand has a larger, 7-inch display with the added advantage of color thanks to its backlit LCD. The LCD means relatively poor battery life and sunlight/glare issues. Barnes & Noble offers e-textbooks in the form of its NOOK Study, but selection of titles is limited.
Next to fall is Kobo. Its eReader Touch is very similar to the NOOK Simple Touch and the same reasons that make it a decent choice as a personal e-reader also make it a poor choice for school. Kobo's e-bookstore isn't a great source of textbooks either.
Sony offers a ranger of e-readers, all E Ink based models. While most fall under the too small category, the company does offer a 7-inch model, the Reader Daily Edition. Sony's online e-bookstore does carry digital textbooks, but the selection can't match Amazon's. There is also no rental option for e-textbooks through Sony, although the touchscreen Sony has the advantage of choosing from a virtual keyboard or freehand writing for taking notes. At $299, it's a little expensive as far as e-readers go and this model is likely due for a refresh in a matter of months, so there's also the potential for buyer's remorse.
Apple's iPad and iPad 2 are excellent multifunction tablets and they dominate the tablet market. A number of companies are producing innovative, interactive digital textbooks for the iPad and it has the added advantage of being able to handle other tasks — web browsing, e-mail, music and movies and even gaming. On the downside, an iPad is expensive ($499 and up), heavy (over a pound), it's LCD display is difficult to read outdoors or in situations where glare is a factor and its battery is only good for 10 hours or so on a charge.
The Winner
While Sony Reader Daily Edition and Apple iPad both offer some compelling features, the winner for 2011 is the Amazon Kindle DX. Not the Kindle 3G or Wi-Fi (they suffer from the same display size issues as most consumer e-readers), but the big brother of the family.
While its $379 price tag is steep, the Kindle DX still comes in well under $100 below the price of the cheapest iPad. And for that $379, you get an iPad-sized 9.7-inch display with E ink Pearl. It looks great indoors and even better in the sun. You won't be stowing this e-reader in a pocket, but any smaller and the display would require too much scrolling with texts and at 18.9 ounces (just a smidge less than an iPad 2) it's still a lot easier to carry than the armload of heavy books it can replace.
While it doesn't have Wi-Fi, the Kindle does offer free 3G connectivity that lets a student download e-books, easily access Wikipedia (or check their e-mail) for free, without having to be in a Wi-Fi hotspot. Battery life is good for two to three weeks with the 3G turned off. Key features like a dictionary are included, as well as the ability to take notes (although the physical keyboard and button based controls make this more awkward than on the Sony); as an added bonus, Amazon synchronizes those notes to your account, so if you open an e-textbook on a computer using Amazon's Kindle app, the notes are carried over.
The icing on the cake is Amazon's Kindle Textbooks. Amazon has inked deals with many publishers, offering a solid selection of e-textbooks for the Kindle. Some of the titles are even available for rent, an option that can shave costs significantly. These are Kindle books, which means they are incompatible with other e-readers, but they are accessible by using a Kindle app on an iPad, PC or other devices.
As I said from the start, no one e-reader is currently the perfect solution, but for now, the Kindle DX is the best of the bunch when it comes to an e-reader for school use.