Two months ago, I made a startling decision.

Actually, I made two startling decisions—the second being a direct result of the first—to leave behind my MacBook Pro during an overseas vacation. This may not be so profound to some, but it was for me. Why? In the past 10+ years, four successive Macintosh laptops have served as my primary computer up until my purchase of a Mac Pro a few months ago. Even though my next laptop upgrade will probably only be a MacBook and not a MacBook Pro, I have no plan to ever not own a laptop, and portable computing has accompanied me on my vacations. All of them. Even weekend trips from Orlando to visit my parents in Tampa saw whichever laptop I owned at the time along for the ride more often than not.

But in early July, as I prepared for a 10-day trip to the United Kingdom, my goal was to pack as lightly as possible. You see, ever since I acquired a ZÜCA Pro, first used during my trip to the 2009 Macworld Conference and Expo, I made a vow to myself: from that trip, onward, I would never again check baggage on a plane if I didn’t absolutely have to. This U.K. trip would see me flying across the pond, as opposed to only flying across the country, and I recalled the occasional nightmares with my checked baggage. I realized those nightmares could grow exponentially should I have problems while traveling abroad. No, I was most intent on only bringing what I could easily carry myself.

For the Macworld trip, in addition to cramming a week’s worth of clothes into the ZÜCA, I also miraculously stuffed my laptop computer, its various supporting equipment, a Nikon D90 with a 24–200mm lens and dual-slot battery pack, boxes of ATPM business cards I’d had printed for myself and two other attendees, and a few other necessities for the trip into a Slappa Velocity Matrix backpack.

I managed fairly well in San Francisco with this large backpack. However, it only barely fit under the airplane seat. Also, after the first day of roaming the Expo halls carrying this backpack all day long, it ended up staying in the condo room for the rest of my excursions. I had absolutely no intention of wearing the big thing around the U.K., and I knew I would be doing a lot of walking in the various towns I’d be visiting. Yet, I would still need a pack of some sort to carry the camera, a water bottle, train tickets, etc.

That’s when I chose to go without the computer. Those who know me are well aware of my penchant for staying connected, and that’s why this big decision immediately gave way to the second: I would perform the process known as jailbreaking to unshackle my iPhone from the clutches of Apple and AT&T, allowing me to depart from the AT&T SIM card and use one from a U.K. carrier.

Sure, there are those who would think nothing of doing this to avoid the exorbitant costs of using it overseas, but I’m something of a rule-follower and have never had any intention of possibly messing up my phone by doing something I’m technically not supposed to do.

Two events coaxed me to do it. First, earlier this year, a friend and former ATPM staff member did the same thing with his iPhone. He answered my questions about his experience and pointed me to the tools—ultrasn0w, among others—that I’d need.

The second event was the release of the iPhone 3GS. No, I didn’t buy one, and I still haven’t. I don’t wish to spend $399 on something when others are only paying $199, especially when it’s not a bad bet that a fourth-generation iPhone could be out next year. However, if the jailbreak had rendered my iPhone 3G irreversibly nonfunctional, I had resigned to this being an excuse to buy the 3GS for $399.

With the iPhone successfully unlocked and tested on a colleague’s T-Mobile SIM, I picked up a Lowepro Fastpack 100 (alternate view #3 gives the best visual of its small size) to hold my Nikon D90, Garmin nüvi 775T (iPhone maps did fine for me walking around towns, but the Garmin is far better-suited for road trips), two international power outlet adapters, various cables and chargers, my passport, a mini first-aid kit, and a water bottle.

Shortly after arriving in Manchester, I made my way to an O2 store (the official iPhone service provider in the U.K.) and purchased a Pay-And-Go SIM card. Being in a rush to catch the next train, I failed to test that I had usable data because the store clerk told me it usually takes a little while, but not more than an hour, for the data to kick in. To my frustration, however, the all-afternoon train ride from Manchester to Exeter was without Internet access.

The O2 store in Exeter was already closed by the time I arrived, so it wasn’t until the next day that I learned I had to modify the Cellular Data Network settings for Pay-And-Go data to work. If the clerk at the shop in Manchester had told me that, I’d have enjoyed being online during the train trip. There was even a power outlet on the train to keep the phone charged.

(Unfortunately, I cannot provide a direct link to the Cellular Data Network settings help page on O2’s Web site due to dynamically generated URLs. If you wish to learn about these settings, start at the iPhone Help page, click “iPhone Setup” in the blue menu bar on the left-hand side of the page, then “Activation Help For New Customers” in the middle of the page, and finally “How do I change my Pay & Go iPhone data settings?” on the Activation Help page.)

Once the data was functioning properly, I quickly realized I would do just fine without the laptop. I never got behind on friends’ Twitter updates, and I stayed mostly caught up with friends’ updates on Facebook. What little bit of non-spam e-mail I generally receive was easily handled on the iPhone, and I was mostly consistent in posting photo updates of my journey for friends and family. (In addition to these iPhone pictures, several favorites from my hundreds of photos taken with the Nikon D90 are available as this month’s desktop photo series.)

Click to enlarge.

I feel my experience is a real testament to how far smartphones—and the iPhone, in particular—have advanced in the past two or three years. I remain astounded that the iPhone performed so admirably with every online task I threw at it: from looking up prices for attractions on Web pages, to using the iTrans application to help me plan which London Underground trains I needed to take, and even purchasing advance train tickets. I had considered posting blog updates as I traveled, making use of the WordPress application, but my desire to tell my friends what was happening was adequately quenched by Facebook and lots and lots and lots of updates on Twitter. As it turned out, the only times I ever wished I had my laptop was to download pictures from the D90 and upload them to my home server. But at 4–7 megabytes per photo, it was probably a good thing that I saved this task until I got home.

Would I do it again—a visit to the United Kingdom with only the iPhone and no laptop? Not only would I, but I’m already thinking about whether I can return next year.

The laptop computer is in no danger of being usurped by smartphone usage. Case in point, I would definitely not have typed this article on my iPhone! But my strong advice to any vacationer who owns an iPhone is to follow my lead and leave the laptop behind if you have no solid, inescapable need to bring it.

P.S. Yes, I really am a rule-follower. Just a few days after returning home, I restored my iPhone back to its non-jailbroken state!

Copyright © 2009 Lee Bennett, lbennett@atpm.com. The Segments section is open to anyone. If you have something interesting to say about life with your Mac, write us. Photos appear courtesy of Apple.