I run headless so don't run into that problem... it would be nice to get some more power so I could plug in a hard drive without having to use a USB hub, though. Tried it a few times without a hub and the drive keeps clicking - spinning down may be the right term? So I've held off on using it as a media center which is what I really want to do.
The power circuits were revised quite a bit in the B+ (and 2), and also between early spins of the Pi and later ones. You may have better luck with a later board revision - I have a Pi B from the very first batch and it can barely keep a backlit keyboard going, but never bothered returning it because I don't use its USB anyway. There's also a lot of flaky USB power supplies out there - make sure yours is solid.
