I would echo what tsl said. I don't like riding without foot retention; on flats I need to think about foot placement, weighing the pedal over bumps, trying to keep traction on the pedal when I go into a skid (usually on snow) etc. With toe clips and clipless, my feet stay on unless I want to put it down, then they magically unclip (it's just second nature). Toe clips take longer for me to get out of.
On the crash note...I haven't had any crashes with other objects (vehicles, peds, etc), just ones due to handling while mountain biking and commuting on snow/ice. On snow/ice, I generally go down fast enough that I don't get unclipped (especially true before I bought studded tires). In these situations, I feel fine attached to the bike; I just slide along, unclip once stopped, dust off the snow, and keep riding. In both mountain biking and commuting, I have had numerous situations where I would have crashed had my feet been disconnected from the pedals, so for my riding style/skill, I think they are probably safer.