After months of speculation, Apple finally announced (well, sort of) that it will be showing off the next generation of the iPad by inviting media to a March 7 event in San Francisco.

Apple is still indisputably at the top of the tablet market, but the next iPad (which most people are calling the iPad 3) faces a host of competitors that are clamoring after their own little niches. There is no tablet out there that surpasses the iPad 2 on every level, but here are 20 tablets that — in one way or another — distinguish themselves from Apple’s gadget.

Kindle Fire: Amazon’s seven-inch tablet has a price advantage over the iPad, starting at $199 instead of Apple’s $499, as well as access to Amazon’s huge retail store.

Nook Tablet: Great for reading, the Nook Tablet’s screen is easier on the eyes than the iPad and, with its seven-inch form factor, easier to carry around.

Acer Iconia A500: This tablet has more memory than the iPad 2 and more ports, making it good for people who want to use their tablets in conjunction with other gadgets.

Asus Transformer: The Transformer line comes with a full QWERTY keyboard, making it much easier to type on for longer e-mails or short memos.

Asus Slider: Another tablet that has a keyboard, the slider has a cool form factor that’s different than your average “screen surrounded by black plastic.”

HTC Flyer: This seven-inch tablet works well for people who like to write, runs Android Honeycomb and comes with an optional pen for highlighting, annotating and drawing.

HTC Jetstream: Like the HTC Flyer, this tablet comes with HTC’s Scribe pen but also comes with 4G connectivity — a much-wished-for feature for the iPad.

Galaxy Note: Not quite a phone, not quite a tablet, this five-inch hybrid comes with a stylus and is good for people who want their tablet more portable than the iPad but don’t want to squint to read on a smartphone.

Galaxy Note 10.1: With all the stylus features of its smaller sibling, the Galaxy Note 10.1 has HSPA+ connectivity, which means 4G data speeds.

Pantech Element:Three words: Waterproof. 4G. $300.

Galaxy Tab 10.1: This near iPad clone has been out for some time now but is a tad bit lighter and, of course, supports Flash.

BlackBerry PlayBook: The PlayBook’s smaller form factor and integration with BlackBerry smartphones recommend this tablet to its very specific niche.

Sony S: Sony’s got great design chops, and this tablet’s folded magazine design fits well in hand — better than Apple’s super-sleek slate.

Sony P: Sony’s latest tablet has not one but two 5.5-inch screens, making it quite portable and, if nothing else, different.

G-Slate: This tablet has 3-D capability. Sure, it requires those red-and-blue affairs, but it’s neat enough if you’re into the gimmick.

T-Mobile Springboard: Super-cheap and with 4G capability, this tablet is good for people who are on the go but don’t fear the two-year contract commitment.

Motorola Xyboard: The update to the Xoom, the Xyboard beats the iPad 2 in the camera department, with an 8MP sensor.

Toshiba Thrive: Ports, ports, ports set the Thrive apart from the iPad 2. The bigger version come with a spots for full HDMI, USB and an SD card, while the smaller version builds in mini- or micro-versions of all those expandable options.

Asus Transformer Pad Infinity: This new version of the Transformer Pad Infinity not only has the keyboard and the cameras, but comes in a range of attractive colors.

Asus Padfone: Another hybrid device, the Padfone lets users click their smartphone into a 10-inch shell to up the display size of whatever they want to do on-the-go. The Padfone can also use the Asus keyboard dock, making it functionally three devices in one.

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