Apple pulls back the curtain on the eagerly awaited refresh of its blockbuster iPad 2 tablet. New features include a better display, a faster chip, and 4G LTE.

Apple CEO Tim Cook wraps up the event by touting the new iPad. “We have redefined once again the category Apple created just two years ago with the original iPad,” he said.

Apple unveiled a new iPad today, resetting the goal line again even as competitors scramble to catch up in the burgeoning market for tablets.

The new iPad–not the “iPad HD” or “iPad 3” as previously rumored–offers a higher-resolution Retina Display similar to that of the iPhone 4 and iPhone 4S. It offers a resolution of 2,048×1,536–or 3.1 million pixels. It also features an updated processor–which the company boasted was four times as fast as the nearest competition–as well as a 4G connection.

Apple also cut the price of two models of the iPad 2 in an effort to stay competitive with lower-priced options.

The new iPad debuts at a time when rivals have flooded the market with competing tablets–with varying levels of success. A year ago, Apple had essentially lapped most of the competition when it launched the second iteration of its iPad, allowing it to dominate the market.

A year later, and it’s a different scene.

While there are still plenty of flops, including Hewlett-Packard’s TouchPad and the Motorola Xoom, legitimate competitors such as the Amazon Kindle Fire have emerged, as well as the Asus Transformer Prime.

Some offer innovations that Apple’s iPad lacks. Nevertheless, with Google still figuring out its tablet strategy with Android, Apple has a decent amount of breathing room.

The new iPad’s pricing scheme is similar to that of the iPad 2. It costs $499 for the Wi-Fi-only 16GB version; $599 for 32GB; and $699 for 64GB. For 4G, its $629 for 16GB; $729 for 32GB; and $829 for the 64GB version. Apple plans to launch it March 16 in the U.S., Canada, the U.K., France, Germany, Switzerland, and Japan. As with the prior versions, the new iPad is available in black or white.

The latest version features an A5X processor, upgraded from the A5 chip used in the iPad 2 and iPhone 4S. Apple says the A5 chip is twice as fast as Nvidia’s Tegra 3 quad-core processor, while the A5X is four times as fast.

The latest iPad also marks the first Apple device to tap into the superfast 4G LTE network. Apple senior marketing executive Philip Schiller talked up the benefits of a next-generation cellular network. Like many other 4G devices, the 4G-connected iPad will be able to double as a personal hot spot. Schiller said there would be two versions of the iPad compatible with LTE, one for Verizon Wireless and one for AT&T. Both will be able to move back down to 3G in areas where 4G isn’t available.

Like the iPhone 4, the iPad features a backside 5-megapixel camera that allows for 1,080-pixel video recording and image stabilization.

Apple said the battery life will remain the same, at roughly 10 hours, though it will drop down to 9 hours when on 4G. The device will weigh 1.4 pounds.

The tablet has emerged as a crucial component of Apple’s revenue stream, standing equal among the iPhone and MacBook businesses. In the fourth quarter alone, the company sold 15.4 million iPad units, placing it head and shoulders above the competition.

Apple CEO Tim Cook, speaking at the event, said the company’s three post-PC devices–the iPhone, iPod, and iPad–sold 172 million units last year, which made up more than three-fourths of Apple’s revenue.

“In many ways the iPad is reinventing portable computing, and it’s outstripping the wildest of predictions,” he said, noting the iPad sold more units than any other PC maker sold PCs in the fourth quarter.

Perpetuating the lead is the wealth of apps that are custom designed for the iPad, something other tablet manufacturers lack. Cook said there were 200,000 apps designed specifically for its tablet.

Apple, however, isn’t immune to competitive pressure, and today’s announcement shows it. The company lowered the price of its 16GB, WiFi-only iPad 2 to $399, and a 3G version for $529. That makes it more competitive with the lower-priced devices on the market, including the $200 Kindle Fire, Barnes & Noble’s Nook Tablet, and the discounted Research in Motion PlayBook.

It’s the same strategy Apple has employed with the older models of the iPhone, including the 99-cent iPhone 3GS and the $99.99 iPhone.