The best thing about USB is that it completely did away with a big tangled pile of proprietary data-and-power connectors that we used to have to rely on to power our gadgets. That was a huge step forward for humanity, but the scourge of proprietary connectors remains in the form of laptop power cords and the like. The next generation of USB might take care of that, too.
Dealing with proprietary connectors and power bricks for laptops isn't just annoying: it's also expensive, wasteful and (let's be honest) just another way that manufacturers try to squeeze more cash out of you. Companies like iGo have had some success in mitigating the pain, but a look at its catalog of connector tips reveals just how ridiculous things have gotten: there are hundreds of power connectors, each one just slightly different enough from the next to make interchangeability impossible. It's so stupid it has to be deliberate.
It's looking like we may be close to solving this problem with USB, which is the way that it's been done with cellphones. A new specification for USB Power Delivery provides for up to 100 watts over a beefed-up USB cable, which is more than enough to power almost any laptop you can buy. The spec includes intelligent power management that can pipe through one of five different voltage/amperage combinations (ranging from five volts at two amps all the way up to 20 volts at five amps). It's smart enough to switch profiles on the fly, send power in either direction and (supposedly) check at either end to make sure that you don't blow anything up with the wrong voltage.
Since this is just a specification, nobody is really ready to offer up any hardware yet, but when it becomes available, we're potentially talking about the end of power connectors. Instead, your laptop will just come with a bevvy of USB ports, and plugging one of those into the wall will bring you as much power as you'll ever need. (Unless your computer is some universe-sized quantum processor or something.