I am a huge Mac fan. Many years ago I replaced my PC's at home with Mac's because I got tired of troubleshooting issues in our home network and playing technician. I did a video using a new Mac, and liked it so much, I did a wholesale replacement, which was 5 other units (lots of kids). I have since moved to using a Macbook at work and am loathe to ever go back. That said, I am also reluctant to buy new things just because they are new. I need to be able to justify why the "new toy" is really needed.
About a nine months ago, while I was still resisting buying an iPad (which I totally wanted), I flew in coach from Chicago to San Francisco. I tried to open my Macbook, but the guy in front of me reclined his seat, and that was that. Unless you are in a bulkhead, or can convince the person in front of you that flying while sitting straight up is an advantage, then you can basically kiss the computing experience goodbye. And on this particular flight, I really needed to get work done. Shortly into the flight, I look across the isle, where the guy beside me is working on his iPad. I will admit, I glanced over to get an idea about what he was really doing. Movies maybe? Fruit Ninja? Golf? Nope, he was working on a presentation, I suspect in Keynote (which would likely be converted ultimately into PowerPoint). He worked until the flight attendant shut everyone down.
That was my epiphany. The beauty of the iPad (and my own subsequent justification) was it's ability to be productive in otherwise unproductive circumstances. This is largely true for commuter trains for the same reason. The added benefit is that, unlike powering up my Macbook, I can power up and down in a second.
That day I went to the Apple Store in San Jose to get an iPad. It was so crowded on a Tuesday afternoon at 1:30 (what was up with that?), that I ended up later in the store in Palo Alto finally getting one. I use it all the time, especially on flights and trains, which is half my life. I sorely underestimated how much more productive it could help me be.
And now I sit here, flying to San Francisco from Chicago, working on my iPad. If you travel allot, and especially in coach, I strongly recommend one.