Its kinda limiting. That's means I have to lug a hub around with me at all times, a spare port would be nice for phone charging, usb drives, etc.
And even if you run out of juice, you can probably recharge it within 30-60 minutes. So it would only mean this long without a usb drive.
Finally, who knows - perhaps Apple will turn the power brick into a usb hub.
One port that can do power, data, or video is pretty spiffy. Using that as an excuse to only have one port on the entire machine seems a bit extreme. At least give us one on each side..