Well, I must chime in on this thread. I'm the queen of "I can't ride with both feet clipped"...and I had a million reasons. I bet I rode one foot clipped in and the other out for a few months...for me,
it was more like the 3 Stooges trying to swallow a pill. My riding
"honey" and I had a couple of really fine "F-you, no, F-you"-fueds right there on the trail over my insisting that the pedal was too tight/too loose over rocks. I was always clipping out on rocks just in case...Sigh...I'm very athletic, but this was the worse learning curve I've ever experienced. Of couse, that now makes me an expert! (ha!)

Using a spin bike or home trainer is very practical advice. I also practiced on a quiet back street that had a circle so I could ride up on the grass/off the street in case I had to--I also took my tri-tool and some teflon lube along, and, would frequently get off the bike and make ajustments to the cleats/pedals. In that way, I taught myself to adjust everything until the clipping motion was no different that unsnapping/snapping on a piece of clothing.

As far as equipement goes, I use SPD's. I think if you're a roadie, you're a lot more concerned with cornering, weight, ect. than mountain bikers. But then of course, I'm looking at upgrading to the Speedplay frog...from what I'm reading, I really like the sound of this product line.
Terry