The FAA notice of proposed rule making (NPM) for UAVs is on the street and has about 30 days left in the comment period. FAA intends to regulate all UAVs. In fact, a close reading and depending on your interpretation, folded up paper gliders could be covered.
I sail boats and am a member of the Academy of Model Aeronautics (AMA). I've been flying radio controlled models for over 50 years and am a flight instructor in my club. The NPM, as currently written, will not cover model aircraft, flown as a hobby, and flown with the pilot in direct control in a "see and avoid" situation. This appears to mean first person video, (flying with goggles showing the view from a camera on the plane) will be covered in the NPM. Anyone flying for commercial purposes will be required to obtain flight authorization from the FAA. Everyone not flying a model aircraft as a hobby will require authorization from the FAA to fly.
Many quad and hexicopter UAVs are stable and have on board GPS navigation. Some do not. Many (most) have camera capability, photos, video, or both. Some can relay the video in real time, some can not. Both visible spectrum and/or infrared cameras can be carried. Visible spectrum cameras can see through windows. IR cameras cannot.
The issue of privacy and personnel space is a real. These things can hover or circle for some time and take video of you the whole time. Most folks would object. Flying overhead structures, vehicles, and personnel is simply not safe. If it flies, it can go out of control. A 3 pound object hitting you at a velocity of 20 mph can kill you. The odds are it won't go out of control, and if it does, the odd are it won't hit you, but the possibility is there.
Like anything else, if used responsibly there won't be an issue. A responsible person could use the item to inspect rigging, top of mast, etc. However, if in a marina, in proximity to other boats or persons, that is an issue. Depth perception while flying in the vicinity of many small lines is problematic. If you nick a blade on a quad or hexicoper, the machine will go out of control. The 2.4 GHz spread spectrum radio technology is much, much better than the 72 Mhz we used in the past, and generally quite reliable. But I've also seen radio interference issues with 2.4 GHz. It is much less common than on 72 MHz, but it can happen. Transmitting video, in the same spread spectrum can affect the radio signal. It depends on the type of frequency hopping scheme, there are several different schemes employed.
At this point in time, with the current technology, most operations are safe if used responsibly. That being said, I will not fly my hexicopter, helicopter, or fixed wing models over, or in the vicinity of structures, vehicles, or people. It simply is not the responsible thing to do.