Amazon (AMZN) boss Jeff Bezos unveiled the new models at an Apple-like press event in Manhattan this morning. “I believe Kindle is an end-to-end service,” he began. “I believe it is because we have been inventing and improving that service over the last four years.” Indeed, that book-driven ecosystem has boosted the Kindle, which currently owns some 52% of the e-reader market. Fortune got up close and personal with the new Kindles:

The Kindle ($79)
This one’s for the e-reader purist who prefers buttons that actually click. In fact, the model hews to the old adage, “If it ain’t broke, don’t fix it.” That explains why it has probably changed the least: the user interface is almost exactly the same, and battery life is still rated at more than a month. The physical keyboard, however, was cut to make the actual reader 30% lighter and 18% smaller, easily reaching a featherweight status of 5.98 ounces.

Now, there are just 10 physical buttons: previous and next page buttons on both the left and right sides (just like before) and a bottom row with six buttons that among other things, take you to settings, the home screen, the previous screen and a software keyboard navigated by four-way directional button. Meanwhile, the back has a rubbery, grippy texture not unlike Barnes & Noble’s (BKS) recently-refreshed Nook.

At a downright impulse-worthy $79, there’s not much to dislike here.

The Kindle Touch ($99 for WiFi-only with ads; $149 for 3G, ad-free)
Think of the Kindle Touch as the bridge between the classic Kindle and the Kindle Fire: it still has the e-ink screen some Kindle readers prefer but integrates the touch-based user experience the new Nook and Kobo Touch — not to mention the iPad — introduced before it.

It’s a solid little slab with a similar-looking plastic front and rubberized texture as the $79 non-touch model, but with fewer buttons. There’s only one front-facing physical button that takes users back to the home screen, while the rest of the navigation is done via swipes, taps and pinches to enlarge and shrink text size. This lends the Kindle a much cleaner, minimal look that’s utilitarian, if not exactly impressive. (The recently-refreshed Nook still wins in the looks department, in my opinion.)

The interface stays largely the same, though there is one notable addition with “X-Ray.” This takes e-reader footnotes to another level by pulling, aggregating and displaying references in a book — notable items, characters/people and phrases — in one screen. The innovative feature allows users to see how many times these “bones” are referenced and tap a scrubber to reach those points in the book. For now, X-Ray is only available on the Touch — one Amazon executive said the company did so to differentiate the e-reader from the rest of the line — but eventually, it will make its way to other models.

The Kindle Fire ($199)
Amazon’s worst-kept secret is finally out in the open. Much of what the tech blogs reported proved true: a 7-inch color backlit screen, a $199 price point, a customized version of Android and a chassis that looks a lot like the BlackBerry (RIMM) PlayBook with a thinner bezel. Under the hood, it’s packing a faster processor than previously expected: a 1 GHz dual-core OMAP4 processor. That should be powerful enough to keep apps humming along.

Really though, it’s all about the software, a cohesive-looking experience integrating many of the features Amazon has built out over the years — an mp3 service, the Android app store, movie rentals — that the company developed to ensure that much of the users’ content is one click away. The home screen highlights a menu bar up top with categories like Newsstand, Books, Music, Docs and Video, while an Apple (AAPL) Cover Flow-like “recency carousel,” displays all the apps, web sites, books and other content you’ve perused in one fluid-scrolling row.

Though we weren’t allowed to spend as much time with the Kindle Fire as we would have liked, what we saw looked promising. Without features like a camera, mic, or 3G option, the Kindle Fire won’t likely cause many iPad users to jump ship. But as far as e-readers are concerned, Amazon has upped the ante yet again.