When the original iPhone arrived in June 2007, it was greeted by massive hype and long lines at Apple and AT&T stores. But a lot of people who were interested in the iPhone held back, guided by a thoughtful and careful technological principle: "Never buy version 1.0."

With the release of Apple's iPhone 3G and its new iPhone 2.0 software, the hype and the lines are back, but the era of iPhone 1.0 is officially over. Those who waited for the second edition of the iPhone will appreciate dramatically faster cellular data access and an impressive software update including a raft of third-party programs. For original iPhone buyers, however, the iPhone 3G is only a must-have upgrade for those who will take full advantage of the fast 3G data network.

Hardware

At a casual glance, the iPhone 3G looks just like the original iPhone (). Front and center is its bright, beautiful high-resolution 3.5-inch diagonal touch screen, offering a resolution of 480-by-320 pixels. It's only when you look at both models side by side that you notice the face of the iPhone 3G is slightly wider, allowing a bit more black space between the sides of the screen and the chrome frame.

On the bottom, the black speaker and microphone grilles of old have been replaced by two oval cut-outs with recessed silver grilles. Between the grilles and the iPhone 3G's dock connector are two recessed Philips screws. It's not every day that you find an Apple product, especially a slick consumer-electronics product, that's got visible screws.

At the top, the most obvious change is the replacement of original iPhone's recessed headphone jack--which required the use of an adapter in order to attach most non-Apple headphones--with one that lies flat. That recessed jack was one of the most ridiculous design decisions in the original iPhone, and it's great to see that Apple has addressed the problem and made the iPhone 3G accessible to just about any set of headphones in existence.

The iPhone 3G's left side includes a volume rocker switch and a sliding switch to place the phone into silent/vibrate mode, just like its predecessor. These buttons, as well as the Sleep button on the phone's top, are now made of metal rather than black plastic. While they're a pretty silver color, the metal edges are also much sharper than the original iPhone's plastic ones, and they press uncomfortably into my fingers as I'm using them. I also found the iPhone 3G's Vibrate switch to be more difficult to slide than the original model's, though that extra resistance does mean it's less likely that your phone will slip into or out of silent mode by accident.

Although it's more curved (and therefore thinner) than the original iPhone at its edges, it's slightly thicker in the middle. However, your hand curves to hold the phone (unless you've got really small hands), and that curve is where the extra thickness is, making it undetectable. Apple truly designed the iPhone 3G to feel identical to the original iPhone.

The iPhone 3G's back is curved shiny plastic (available in black or, in the 16GB model, black or white), rather than the flat matte aluminum of the original model. Whether that's better or worse is a personal, aesthetic choice, although the plastic case shouldn't block radio signals as much as the aluminum did. However, the shiny plastic is much more adept at collecting fingerprints and smudges than the old textured aluminum.

The curved back does make the iPhone 3G slightly unstable when laid on a flat surface, but it only wobbles slightly, and I found it acceptably stable for typing and tapping. There's a gap between the sides of the iPhone's display and the edge of the phone itself, making it unlikely that you'd touch close enough the edge to cause the phone to wobble dramatically. The extra width also makes typing on the iPhone with two thumbs slightly more