Include USB charging port(s) on laptop power supply (maybe even hub/data functionality)
First, the simple part of my request: Include one or more USB charging ports on laptop power supplies, so one can charge a laptop and USB device(s) without having the device(s) drain power from the laptop that you're trying to charge. At least one third-party brand does this: Cables Unlimited (PWR-LAP-UD120)
Now, to make it even slicker: Build some intelligence/connectivity into the supply (and the laptops to which they connect) that allows it to act as a USB hub for the laptop, which would be particularly useful in conjunction with smaller laptops that have few ports. USB hubs are a dime a dozen, but they're one more thing to carry, plus you still have the issue of them draining power from the laptop and/or requiring more power than the laptop's ports are capable of providing.
Alternately, If this is not worth the R&D to engineer or too inconvenient for the end-user (possibly being several feet away from the laptop itself), add one or more separate, powered USB connections branching out from the cable that connects the power supply to the laptop (like the secondary male/female connections on USB-powered CD/DVD burners); one can connect a USB device into this powered connector, which in turn can be plugged into the laptop's USB port...the power supply would take care of the charging while still providing data connectivity with the laptop.