El Gigante

+1 on the Shimano M324's. I use these on my Specialized Hybrid for commuting and they work great! Part of my commute takes me through downtown Los Angeles, and a couple of blocks are real white knucklers, (busses, bumper to bumper traffic, road construction with narrow lanes, etc.) I can use the platform pedals to navigate through the rough stuff, and then flip them over and clip in after it clears. With the recessed shimano cleat on my bike shoes, its relatively easy to walk on sidewalks, and also pedal on the platform side without your foot sliding off the pedal.

As other posters have said, part of riding clipless is becoming comfortable with the motion of clippping in and out. Practice clipping in or out in a big parking lot or other uncrowded area until it becomes routine, then having to clip out when you're on the street won't seem so scary. In the end, it does'nt really matter whether you ride clipless or on platforms, just keep riding and use whatever feel more comfortable with. Good luck and stay upright!!