I just wrote a long post on this for someone else and was trying to remember who and where, so I could copy and paste, but I give up.
All modern electronics now use what are called Switch Mode Power Supplies (SMPS) because they are smaller / cheaper / much more energy efficient than older linear power supply technology. The only down side of SMPS technology is that in the way they work, they create what's called "common mode noise", electrical noise / current referenced to ground that is always seeking to return to its source, the SMPS. Because of this, they NEED the ground reference as a return path to the power supply, otherwise that CM noise ends up circulating around inside of the equipment adding thermal and voltage stress to the electronic components and shortening their useful life. For really small SMPS, like what you have in a cell phone charger, they can make it double insulated and hardened against CM noise relatively cheaply, so that's why you see those units with 2 prong plugs. But as the power requirements go up, so does the cost to do that, so most mfrs just use a grounded plug connection to allow that return path of the CM noise to its source. That means then that the electronics MUST have a grounded connection, not just because of safety concerns, but for the long term integrity of the devices.
You can get around the shock safety issue of an ungrounded receptacle by adding a GFCI to it (406.4(D)(2) ), but the risk to your electronics is not helped by that. That is what is behind the addition of 250.114(3)(b) to the NEC, I think in the 2002(?) code and the addition (also in 2002) of 250.130(C) to allow for adding an equipment grounding conductor to an older in place circuit.
