From the moment Google first announced Ice Cream Sandwich, or ICS, the fourth generation of its Android operating system, we’ve been waiting to get our hands on the flagship device that would run this storied piece of code.

Google teased out ICS information bit by bit, beginning with a taste of the OS at its I/O developer conference in March. Then, just about a month ago, Google and Samsung unveiled the Galaxy Nexus, the next major Android smartphone release.

The Galaxy Nexus is the latest in a line of flagship device launches for Google, a program it began after collaborating with HTC to launch the first Android phone, the HTC Dream, in October 2008. Working closely with a single manufacturer, Google prepares each major iteration of Android for launch with a brand new device. The practice eventually became what we now know as the “Nexus” program, beginning with the HTC Nexus One almost two years ago.

And now, finally, the ICS flagship has arrived. I’ve spent about eight hours running the smartphone through its paces, and here are my first-look impressions.

First and foremost, it’s massive. Unlike any previous Nexus model, the Galaxy’s display measures in at a sizable 4.65 inches; it’s one of the largest of all currently available smartphones. Similar to last year’s Nexus S, the plastic bezel wrapped around the Galaxy Nexus’ screen is incredibly thin. Instead, nearly every square inch of the phone’s face is devoted to fine glass construction.

And rightly so. The ICS operating system doesn’t require physical buttons. It replaces them with software keys, the same set implemented in Android 3.0, aka Honeycomb, which Google created for tablet deployment. The new virtual buttons are unobtrusive, anchored modestly to the bottom of the screen, yet shiftable to the side if, say, you tilt your phone into landscape mode to take a photo.

The virtual buttons are akin to a three-pronged version of Apple’s home button, only with more versatility: “Recent apps” takes you to a scrolling view of what you’ve used lately, while the “Back” and “Home” keys…. Well, you get the idea.

More importantly, the ICS home screen just looks right. The newly revamped interface is replete with cool blues, metallic grays and lots of swishy animated effects. Much of the enchanting vibe would be lost on an inferior display, but the Galaxy Nexus’ 1280 x 720 Super AMOLED screen delivers all the crisp, clear image quality that makes hardcore mobile enthusiasts flock to Samsung display technology.

The phone’s chassis doesn’t immediately inspire build-quality confidence. Unlike rivals HTC and Motorola, Samsung is prone to pushing out lightweight devices built mostly of airy plastics and minimal exterior metal. I’ve always been partial to gear with more heft, but others may dig this phone’s lack of, well, density.

Somewhat disconcerting, however, is the thin plastic backing that separates the phone’s delicate cellular innards — including a 1.2GHz, dual-core processor, and 1GB of RAM — from the harsh outside elements. This strip of resin, while pleasant enough to the touch, seems far too flimsy to serve as any sort of reliable protective cover. Take heed, my butterfingered brethren.

Otherwise, the Galaxy Nexus is a slick-looking piece of hardware, almost teardrop-like in profile with a wide bottom that tapers as the eye moves upward. Though scaled up considerably in terms of size, Samsung’s design brief hasn’t strayed far from the previous generation of Nexus hardware. In fact, this model retains the slight plastic lip on the lower-back part of the handset. Is this lip functional or mere flourish? We’ll dig further, and get back to you.

My personal favorite hardware feature is the Nexus’ snappy rear-facing camera. On paper, its 5 megapixels don’t sound like a whole hell of a lot, especially considering many of today’s high-end Android phones come standard with 8 megapixels. Google says it isn’t interested in a megapixel spec war with other devices, and instead wants to speed up its phones’ shutter speeds and response times between shots.

Well, they pulled it off. Firing off multiple shots in succession is a breeze, and lag between photos is basically a thing of the past. Between the quick response times and a new feature that lets you go straight from your lock screen to the camera app with a flick of the thumb, you’ll never miss a think-fast photo-op again.

After all of my fawning over the hardware, I must admit: However compelling the Galaxy Nexus is at first sight, the star of this show isn’t made of glass and plastic. No, it’s the software underneath. Check out our first impressions of Ice Cream Sandwich in our companion piece, and expect a full review of the Samsung Galaxy Nexus next week.

Photos: Ariel Zambelich/Wired.com