When I travel for work, one thing I really miss about the comforts of home (besides my standing desk!) is multiple displays. I just don't feel as productive if I'm constantly switching windows all the time.
Reluctantly, since I could justify buying a portable monitor anyway (for working on normally-headless hardware without a serial console), I went ahead and purchased a GeChic 1303H 13.3" 1080p Portable Monitor.
Since I don't really need to connect to any older hardware, I just use the included HDMI connector (it seems to be proprietary). The monitor has other proprietary connections for DisplayPort and VGA, but I haven't tested them.
One very convenient thing about this monitor is that I can power it from a USB 3.0 port on my laptop without issue. It works no matter if I'm on AC power or battery.
The monitor also has built-in speakers, but I don't normally use them since I prefer my laptop muted (so that I don't disturb others' work).
I'm happy to say I don't regret it! Now I can sit in a conference room far away from home and enjoy the productivity of a second monitor. The 13" model is thin and lightweight enough that I can fit it comfortable in my bag's laptop pouch, and I can still travel light (without having to check a bag).
The only down side is the fact that often when traveling I'm sitting in a cramped conference room with very little room to spread out. So I don't get to use it in those cases. And I might feel a little guilty about encroaching into the space of the person next to me. ;-) The only other thing I would improve about the product is the bulky USB and display cables that extend somewhat into where I would use the mouse. Cable routing is a minor issue, too, but I just tuck the cables out of the way behind the laptop's power cable.
In summary; I was pleasantly suprirsed with this product, and wouldn't hesitate to recommend it!