Pedals fall into two main categories: flat (usually with toe-clips) and 'clip-less' or 'clip-in' (where a mechanism in the pedal grips to a cleat on the sole of your shoe). The T400 pedals from Shimano (or, to use the full name, the PD-T400 Click'R) are the clip-less variety, but the gripping mechanism is incredibly light, so it's very easy to release your shoes from the pedals. They're a useful option for cyclists keen to try clip-less pedals for the first time.
Like Speedplay's other lollipop-shaped pedals, these Zero Stainless Steel Pedals have a few important differences from most clipless road pedals: they're dual sided; the retention mechanism is in the cleat instead of the pedal; and the cleats attach with four bolts instead of the usual three-bolt road pattern.
Earlier this year, I bought my first road bike. It came with road clip in pedals, some kind of look clone. I also bought some Northwave Vertigo's to go with them. Anyway I just couldn't get on with them so I swapped them for some Shimano SPD M520's and have completed 1000 happy miles. The wife has said she'll get me some road shoes for christmas as I've been wearing my Shimano MTB shoes.
I have managed to lose my cycling shoes (don't ask...I could spit) and I'm mulling over whether to finally make the switch to road - rather than MTB - pedals when I buy some new ones.
I've stuck with my old faithful Time Atac XS MTB pedals for years because I've never really seen the need to use anything else. They're very comfy, and a helluva lot easier to get in and out of than many road pedals I've seen - and I can walk normally in MTB shoes, which is a major bonus if you ask me.
Top of the range MKS pedals (pair) - double sided clip in pedals with MKS's unique removable feature - pull back the knurled ring and the pedal slides off. Ideal for commuters, folding bikes etc. I've done about 100 miles from new on these in the dry, and they're as new. Complete with washers, yellow safety clips (not used), travel bag and two bolt cleats. Lovely quality, super smooth bearings - change in circumstances means I no longer need them. Additional retaining pieces are available to buy separately, allowing an easy swap of one pair of pedals between two or more bikes.