Unlike buying a desktop Mac, purchasing a PowerBook or iBook often means purchasing a bag of some sort to carry it in. But buying a laptop bag can involve as much, if not more, consideration than buying the computer itself. What sort of cushioning will protect your investment? How much should the bag carry? How often will you be carrying it? And what other features should you look for?
For this article, I originally wanted to review a few specific bags, but because there are so many types of bags and ways that people use them, I'm going to take a broader approach instead and look at some of the factors you should consider when buying this essential laptop accessory.
Types of Bags -- In general, you can find four types of laptop bags. For the traditional business look, you can opt for a briefcase shape that sports one handle and possibly a shoulder strap. Briefcase bags range from slim slabs of leather to bulky expandable contraptions that offer more concealed pockets than you may ever need. The largest of the briefcase-style bags even feature wheels and handles for pulling through airports. (As far as I know, none yet feature their own motors, but never say never!)
Bike messenger-style bags tend to be larger than briefcases, with a strap that goes over one shoulder and across the chest. A second strap that connects to the main strap is sometimes included to improve stability (such as when riding a bike, naturally). Some messenger bags consist of just one large pocket where you store everything, laptop included, but you can also buy modified messenger bags that include padded compartments for laptops and accessories.
Backpacks are also popular, especially among students and travelers who prefer to keep their hands free when carrying their gear. Like briefcases, you can find backpacks that hold little more than the laptop and its power cord, as well as beefier models with enough room for your accessories, a few changes of clothes, and maybe even a very small consultant.
For the minimalist, laptop sleeves have begun to gain popularity. Sleeves hold only the laptop itself, sometimes also including an outside pocket for a few sheets of paper or a couple of CDs, though not a power adapter and cord. Sleeves are often used in conjunction with other bags (of all sorts, not just computer bags) to further protect the laptop.
That said, hybrids and variations abound - some bags can be carried like a briefcase, slung over the shoulder like a messenger bag, and also include straps you can extract to carry the bag like a backpack. The specific type of bag is usually a personal choice based on your likely usage patterns; I own two bags I use regularly: a Timbuk2 messenger bag for when I ride my bicycle to work and a Tom Bihn Brain Bag backpack for when I'm traveling or need to carry more than my minimal complement of gear.
Essential Advice -- No matter which bag style you choose, keep the following factors in mind while you're shopping.
Weight is extremely important. My 15-inch PowerBook G4 is pretty svelte at 5.6 pounds (2.5 kg), but I also carry an extra power adapter, an assortment of cables, Palm organizer, iPod, and other stuff that adds up - I don't need more weight added by the bag itself. Although a rich leather exterior looks sharp, I prefer to carry something made of lighter materials.
Speaking of materials, other than leather you'll commonly find bags made of materials such as ballistic nylon and Cordura (a durable fabric manufactured by DuPont). They're resistant to tears and scuffs and provide some level of water-resistance - though be wary of companies claiming their bags as being "waterproof." Cordura or nylon alone won't keep the liquid out over time, and zippers and seams are often not properly sealed or treated to keep moisture out. If you really need a waterproof bag (if, say, you bike to work in Seattle every day throughout the year), look into getting a dry bag with a roll-down opening, such as those made by Ortlieb. For the ultimate in rough knocks durability, look for something like Matias Corporation's Laptop Armor case, which has a hard outer shell and a padded foam interior.
Also consider the bag's appearance - not just its color or how fashionably it's cut, but whether the bag is appealing to thieves. Too many bags scream, "Laptop inside!" and make for good targets. (TidBITS contributor Gideon Greenspan took the idea of concealment to one extreme when he embarked on a trip through Asia with his PowerBook sheathed in a padded FedEx box; see "Off the Beaten Track" in TidBITS-508.) Backpacks are good because they can just as easily hold textbooks or papers, and may not be worth a criminal's attempt.
The next consideration is access: can you grab your laptop with one hand? Are the buckles, clips, or straps easy to fasten and release (and can those be done with one hand)? Can you get to the laptop without taking the bag off your back or shoulder? This is especially important if you're a frequent air traveler, because you need to extract your laptop as you're going through airport security (at least in the United States; I haven't had the pleasure of visiting another country lately with my computer gear). For this reason I like a bag with convenient access from the top. In contrast, I actively avoid briefcase-style cases that require you to unzip most of the bag, then undo a pair of Velcro straps which anchor the computer into place. That approach might hold the PowerBook more snugly, but it's simply too much work.
And, of course, perhaps the most important factor is a bag that will protect your laptop from the inevitable indignities that accompany everyday use.
Damage Control -- Although a bag gives you a better way to carry your laptop than tucked under your arm, it should also offer protection from bumps, jostles, and environmental nasties. Just how much depends on your comfort level.
At the least, the bag should have some sort of padded pocket for the laptop. If it doesn't, such as with a single-pocket messenger bag design, get a padded sleeve that holds the computer. Even better are bags or sleeves that incorporate some sort of air cushion in addition to padded material. For example, the Tom Bihn Brain Cell sleeve that I use suspends my PowerBook in a sling - if I accidentally drop my bag a couple of inches, the laptop may not even hit the ground.
Just as important, however, is protection from accidental spills and other mishaps. A problem with many bags is that their architecture doesn't provide support for keeping them upright. The weight of a computer and related gear causes the bag to tip over and disgorge its contents. This may not be a big deal when you're sitting on the floor at the airport waiting for a flight, but if you set the bag on a table and it tips the wrong way, that three-foot drop could cause serious damage.
The construction extends to zippers and clips, too. A friend of ours lost his PowerBook because the zipper on his bag slid loose and the laptop (with some help from gravity) pushed itself out into the open air. We've seen bags with zippers that extend almost the entire way around the bag, which seems like a nice idea for full access, but it also makes certain types of accidents far more likely if the zippers aren't closed properly.
Store, Organize, Access -- With the basics of protection out of the way, make sure the bag will hold the other gear that's bound to tag along, and make it easily available. Cables are notorious space-wasters, so look into buying a separate carrying case for them; heavy-duty ziplock bags also work. Nearly all bags come with some type of pockets for pens and pencils to help prevent ink exploding in the bag.
Specialized pockets are also a bonus. Adam has used a Kensington SaddleBag for years, not just because it holds his PowerBook snugly and includes hidden backpack straps for traipsing around New York City during Macworld Expos, but because it includes a clever pocket on the outside flap that's exactly the right size for stowing airline boarding passes or folded-up maps. (The SaddleBag Pro, which I haven't used, also includes a Junk-It drawer - a plastic slide-out tray at the bottom where you can store cables and other small miscellaneous items.) One unusual pocket you might appreciate is an external water bottle pocket; being forced to carry a water bottle inside the bag with his laptop and other gear always makes Adam nervous.
However, be careful of bags with too many pockets: in my experience, more pockets invite you to carry more stuff, which makes you need a bag with more pockets, until ultimately your idea of a portable computer case is one with wheels that hitches to the back of your car. It's more important to find a bag with just the pockets you need, especially when the designer has put a great deal of thought into size, placement, and accessibility.
It's in the Bag -- If at all possible, try to obtain some hands-on time with the bags you're thinking about purchasing. Computer-supply stores tend to have a moderate selection; Apple retail stores carry a several brands and types; and travel and luggage stores are good sources. A visit to Macworld Expo is also an excellent way to compare bags from a number of manufacturers in person. It's always worth asking your laptop-toting friends, who can give you their hard-won advice on what to look for or avoid in a particular case.
Whatever you choose, keep mind that the state of laptop bag design is continually advancing, and you may find yourself wanting a new bag in a few years anyway. Or you may need a new, larger bag to hold Apple's forthcoming 20" PowerBook G5 (kidding!).