Post by David Pierce. Find me on Twitter.

I work, whether it’s my day job, school, or blogging, from a variety of different places. Sometimes I’m home, but frequently I’m at a coffee shop, or a bookstore, or any number of other places. No matter how odd the location, I need to bot lose any productivity based on where I am.

Because of my endless search for mobile perfection, one of my favorite things to read has always been people opening up their travel bags, and sharing what all is inside. Everyone’s got their own special needs for when they’re working on the go, and tons of people have spent time, money and thought making sure that they’ve got the essentials with them whenever they travel.

I’ve spent a few months figuring out exactly what I need in my bag, and I think I’ve finally got it down.

So, since these things have been so helpful for me, I’ll share with you exactly what goes with me, pretty much wherever I go.

Macbook Pro 13”

I’m three weeks into using a Macbook Pro, and have nothing bad to say about it. The 13’ machine is light, thin, boots quickly, and does everything I need to do. I’ve got a 24’ monitor at home for anytime I need a monster screen, and the portability of the 13” unibody Pro, plus the truly all-day battery life, makes this machine worth its weight in gold.

Forget the Windows/Mac OS X debate. In this case, Apple’s hardware is winning – and that’s really the only thing that matters to me. I’ve still got a Windows PC, but the Mac goes everywhere with me, as the perfect combination of mobile and powerful.

Extra AC Adapter

Every once in a while, despite its freakishly-long battery life, I do need to charge the Macbook while I’m out. Packing, unpacking, and repacking the AC adapter I have at home is a huge pain, so I bought a new one, that lives in my bag at all times. That way, I’m sure to never forget it, and I don’t have to be constantly crawling under my desk at home.

External Hard Drive

Most people carry around flash drives, or burned DVDs, or something like that, but I needed more than that. I have a Western Digital 160GB Hard Drive (though you can get much more capacity now) that gets all its power from the computer, which makes it super-portable.  It’s got all my important documents on it, as well as lots of movies and music for epic entertainment, wherever I go.

I’ve got the hard drive in two partitions, one of which is a bootable disk of Mac OS X. If something goes wrong with my computer on the road, I can reinstall or repair my operating system without much ado. I used it with Windows, too, and it was a frequent lifesaver.

Extra Headphones

Headphones are, well, obvious in their usefulness. I use them with my computer, or my iPod, or whatever mobile device tickles my current ocular fancy (I’ve always wanted to use the word ocular in a blog post. Thanks for that.). I also use headphones for wearing, with nothing playing, just to keep distractions away; for some bizarre reason, headphone-wearers are a total no-fly zone for most people. Disconnected headphones = totally focused David.

Headphone Splitter

This was probably the best $1 I ever spent – except that pack of Skittles the other day. Skittles are delicious.

Amazon sells headphone splitters for all of one dollar, which lets you plug two sets of headphones into one jack, for sharing movies or music with a friend. This is a life-saver on planes, trains, or automobiles. I swear, I didn’t just make that reference on purpose.

3 Magazines

I often have periods of about 5 minutes to kill -  not always enough time to really get into a book, or do something productive on my computer. 5 minutes is perfect for flipping through a magazine, though. I always try to keep three different magazines in my bag – I’ve currently got Wired, Rolling Stone, and Maclife. A few minutes of reading a magazine’s a great way to kill some waiting time.

Various Cables

Three cables live in my bag, and serve most of my necessary purposes. The first, an iPod USB cable, keeps my iPod in sync, as well as serving as a charger in a pinch. The second is a Mini-USB cable, which charges most of my gadgets (my phone in particular) without the hefty AC adapters. I try not to carry too many adapters (most applications I use have some sort of Wireless sync), and those two are the only ones I really need.

Point-and-Shoot Camera

I’m not a huge photography nut. I do find myself, every once in a while, in a spot where I want to take a picture – maybe it’s a piece of paper to send to Evernote, or a great view I’d like to capture. I don’t even own a particularly nice camera, but my simple point-and-shoot does the job, with super-long battery life and without taking up much space.

A Moleskine

I’m constantly writing down notes – everything from blog post ideas, to things to do, to random thoughts about  how creepy the new Toyota Prius commercials are. I mostly use my phone for taking these notes – everything goes into Evernote. In some situations, however, I’ve discovered that pulling out my phone and typing may not be the most PC thing to do – like in church, for instance.

So, for those situations (restaurants, church, while I’m in mid-conversation) where for some reason typing on my phone isn’t appropriate, I keep a small Moleskine notebook around for capturing all my mind grapes.

$36

You never know when you might need to buy a meal, tip a helpful someone, or get a cab to the meeting you’re spectacularly late for. For those things, I keep $36 in my bag at all times. Why $36? That’s a $20, a $10, a $5, and a $1. Keeps me prepared for any situation.

The Bag

All the above things go in my Solo Messenger Bag, which I just got a few weeks ago. It’s rugged, good-looking, full of pockets, and a safe place for all my most important stuff.

For more ideas on the contents of travel and work bags, check out the contents of these people’s go bags:

David Pogue (New York Times)

Gina Trapani, Adam Pash, Kevin Purdy, Jason Fitzpatrick, The How-To Geek (Lifehacker Editors)

Josh Gates (From Destination: Truth)

What’s in your bag?