Like the star on a Christmas tree, iPhone is perched atop all the top 10 gadget lists for 2007, and with good reason. Not only did iPhone revolutionize the way people think about their mobile phones -- as many writing those lists crow -- but in my case, it has changed the way I live.

Let's be clear: I'm not your typical gadget or technology geek. I didn't have a cell phone until 2000, and even then I purchased a refurbished Nokia handset for $30 that resembled the Motorola brick phone Michael Douglas used in the 1987 film "Wall Street."

[Watch the three-part video series  Two Geeks and an iPhone.]

2008 will mark the first year in as long as I can remember that I won't be buying a leather-bound dayplanner to keep track of appointments, and I still read more books than blogs. Though I rampantly text-message, instant-message and e-mail, I'd still rather open my mouth and speak than send a series of virtual messages to have a "conversation."

I covered the iPhone launch here in New York in June and didn't quite understand what all the fuss was about, especially as I interviewed people who lined up for days in the broiling heat just to be among the first to buy the gadget. I am a huge fan of Apple products and own several iPods and a PowerBook, but like many others, I didn't plan to buy an iPhone until the price dropped or Apple came out with the product's second wave.

When someone gave me an iPhone in late August, I surprised myself by being giddy. I immediately chucked my AT&T-powered Motorola Razr in favor of what would become my new main squeeze. At close range, iPhone, like other Apple gadgets, was just so -- for lack of a better word -- adorable. Even before I opened the box, I realized that my love affair with iPhone was about to begin.

Four months later, I'm still smitten. Until iPhone, I never thought a mobile device could so drastically change my daily life. Its cousin iPod was certainly a revolutionary product, disrupting an entire music industry that is still feeling the repercussions. But for the average person, iPod really only changed the form of device that plays your music or videos and how you purchase entertainment. iPhone, on the other hand, affects daily human behavior on a much broader scale.

Soon after iPhone came into my life, I was heading to Brooklyn to see a friend's band perform. Like any self-respecting cabbie in Manhattan, my driver had no idea how to get to the venue, even when I gave him the address. Like most Manhattan-dwellers, I didn't either.

But as we were zooming over the Williamsburg Bridge in the direction I knew we had to go, I used the Google Maps application on iPhone to find the best route. I had it before we exited the 1,600-foot-long bridge in Brooklyn.

Now, iPhone isn't the only mobile device that provides maps or driving directions. But do any of them do it quite as niftily as iPhone does, with just a few taps on a screen? And do they mark your destination on the map with a cute little red pushpin icon so resembling a cherry lollipop that you just might want to lick it?

This is the fundamental reason why my heart, like many others, is aflutter over iPhone. It's not just what the gadget does that makes it a life-changing device, it's HOW it does it -- and, more importantly, how it lets a user do it.