It's usually worth trying out a few different types of pedals, since it's one of the three contact points between your body and the bike, and the one you apply power to. Find a comfortable type and don't worry too much about clipping in if you don't feel like it – it doesn't make as big a difference for most of us as your road-bike friends have tried to convince you.
All pedals nowadays are 9/16" English-threaded (kids' bikes are often still 1/2", a little smaller). We don't stock French-threaded pedals, you'll have to find those on your own, or re-thread your crank arms.
Pedals are right-hand (AKA normal) threaded on the right of the bike, and left-hand (AKA backwards) threaded on the left side. Don't mix 'em up – nice pedals are marked L and R (or G and D if they're made-in-France). You'll need a longer 15mm wrench to remove them, they get pretty tight.
All of our pedals are sold as a pair, left and right.
