6. Do you already own a tablet?

Both Amazon and Barnes & Noble offer free apps that let you read books from their online stores on an existing tablet or smartphone. Reading on a smartphone is fine in a pinch, but it's a chore to constantly turn pages and isn't particularly comfortable. A full-fledged tablet, though, makes a fine reading device, assuming a color screen experience is what you're after. That said, keep in mind that an inexpensive monochrome e-book reader is far more portable than an iPad, the battery lasts much longer, and you can read it in bright sunlight.

7. Do you belong to Amazon Prime?

While it began as a $79 annual service offering unlimited two-day shipping on orders of any size, the Amazon Prime service has branched out in two interesting ways. Members can now download one book a month from a fairly extensive collection for no additional charge (on black-and-white and color Kindles only), and can also stream an expanding variety of movies and TV shows to color Kindles. For Amazon Prime members (or would-be members), there's no reason to stray from the Amazon family, so a Kindle is a solid choice.

8. Do you care about being able to order books from anywhere?

Some e-book readers have built-in 3G cellular connections that let you download books anywhere there's a signal, at no additional charge. 3G e-readers are significantly more expensive, though, and for most, downloading over a Wi-Fi network is convenient enough.

Top Contenders

While there are other companies in the market, there's no good reason to stray from the two biggest players: Amazon with its Kindle series, and Barnes & Noble with the Nook line. Both have online stores with extensive collections of books and periodicals; support from public libraries, which increasingly offer e-book loans; and both black-and-white and color models.

Which e-book readers are most tempting among current offerings? Here are my top picks:

Black-and-White

Amazon Kindle ($79). The value leader in the category, with a top-notch screen and easy-to-use software. Note that the $79 price is for the model with "special offers" (you know, ads). But the ads never show up in anything you're reading — they're just on the screensaver page and the menu page, and some of the offers are pretty tempting. No need to spend $30 more for the ad-free version.

Amazon Kindle Touch ($99 with special offers) and Barnes & Noble Nook Simple Touch ($99). Instead of pressing buttons to move from page to page on these similar readers, you swipe across the screen with your finger, mimicking the motion of turning a physical page. There is also a version of the Kindle Touch with 3G cellular service ($149 with special offers).

Barnes & Noble Simple Touch with GlowLight ($139) uses a clever sidelighting scheme to illuminate the page for reading in the dark, while maintaining the ability to read in bright sunshine and most of the considerable battery life advantage of monochrome screens over LCD.

Color

Amazon Kindle Fire ($199) is an impressive multipurpose tablet with a handsome screen, a straightforward interface that's much easier to use than a full-fledged tablet, access to Amazon's extensive app store and, for Amazon Prime members, no-extra-charge book loans and videos.

Barnes & Noble Nook Tablet ($199 with 8 gigabytes of storage, $249 with 16 gigabytes of storage) doesn't offer the same extensive selection of downloadable video available on the Kindle Fire (though both support Netflix), but it has a feature the Kindle lacks: a memory expansion slot, so you can add up to 32 gigabytes of additional storage for music, video, photos and so on.

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