Amazon’s Kindle may have launched the e-book boom we’re seeing today, but Barnes & Noble’s NookColor brought on a new generation of 7-in. multimedia tablet devices priced to undercut the 9.7-in. iPad. In announcing the Nook Tablet last week, B&N executives made it clear they don’t intend to take a backseat to the Kindle Fire, as both Amazon and B&N have announced aggressive plans for promoting and selling their devices. Come this holiday season, the tablets will be available at a record number of physical retail outlets.

Here’s a guide to four devices now setting the standard for mobile media use and for competing with Apple.

Kindle Fire

Price: $199

Screen: 7-in.color touchscreen

Operating system:

Customized Android OS

Titles: More than one million for-pay titles; 18 million movies, TV shows, and songs; exclusive deal for DC graphic novels; 400 magazines and newspapers.

Apps/games: Thousands of Kindle-optimized Android apps and games

Battery life: 8 hours reading; 7.5 hours video playback

Storage: 8 GB, plus cloud storage (6,000 books, 80 apps, 10 movies, 600 songs)

Connectivity: Wi-Fi

Social media: Twitter, Facebook, Popular Highlights, and Public Notes

Hype: Beyond the e-ink Kindle, Amazon’s new tablet has millions of orders, lots of content, and Amazon Prime shipping. You can even borrow a book.

Nook Color

Price: $199

Screen: 7-in. color touchscreen

Operating

system:

Customized Android OS

Titles: Hundreds of thousands of for-pay titles; hundreds of magazines

Apps/games: Thousands of Nook-optimized apps and games

Battery life: 8 hours reading

Storage: 8 GB built-in; expandable to 32 GB

Connectivity: Wi-Fi

Social media: Twitter, Facebook, and Nook Friends for ratings and sharing

Hype: B&N’s original semitablet is now cheaper, and a forthcoming software upgrade gives it functionality close to the Nook Tablet.

Nook Tablet

Price: $250

Screen: 7-in. high resolution color touchscreen

Operating

system:

Customized Android OS

Titles: Hundreds of thousands of for-pay titles (plus Marvel graphic novels); hundreds of magazines; HD movies, TV shows; NetFlix, Hulu Plus, and Pandora.

Apps/games: Thousands of Nook-optimized Android apps and games

Battery life: 11 hours reading; 9 hours video playback

Storage: 16 GB built-in; expandable to 32 GB

Connectivity: Wi-Fi

Social media: Twitter, Facebook, and Nook Friends.

Hype: Pricier than the Kindle Fire, cheaper than the iPad, it’s got wide viewing angles, fast dual core processing, and in-store support at hundreds of B&N stores.

Kobo Vox

Price: $199

Screen: 7-in. color touchscreen

Operating system: Android 2.3 (standard Android OS)

Titles: One million for-pay book titles; 1,900 newspapers through PressReader; 4,500 magazines via Zinio; streaming music

Apps/games: 15,000 free Android apps optimized for the Kobo Vox; the Kobo App store and access to standard Android apps via Android Market.

Battery life: 7 hours with Wi-Fi off.

Storage: 8 GB built-in; expandable to 32 GB

Connectivity: Wi-Fi

Social media: Twitter, Facebook, Reading Life, and Kobo Pulse

Hype: Just two years old, the aggressive Canadian-based e-book retailer is matching Amazon and B&N device for device and may have the most clever social media technology of them all.