A few words about shoes and pedals. Shoes are good. Pedals are good. The End.
Ok, seriously. Studies have shown that by using cycling shoes you can improve your pedaling efficiency by about 30%. Imagine that over the course of a century ride. You'd have enough energy left to do another thirty miles! Woo Hoo! Or you could finish 30 percent earlier. Or simply use 70% of the energy and then go home and have a nice nap.
Cycling shoes and pedals go together like... like... um... They go together, trust me. It's the whole insert Tab A in Slot B thing, ok? So, your shoes and your pedals must be the same type. There are various types out there, SPD, Look, Time, Eggbeater, Speedplay, and I'm not going to tell you which is best. I won't even tell you which kind I use. But I'll tell you this, I use them. Why not take advantage of one of the quickest and easiest ways to improve your cycling efficiency?
Now, that said, I do want to make some recommendations. You can either get "road" shoes, which are the ones that have the cleats slapped on the bottom as if someone designed the shoe and then said "Oh snap! I forgot to attach a cleat!" Those are the ones that make you walk like a duck and make a ton of noise on a hard surface. Then there are the "off-road" shoes which have the cleats recessed so that you can pick up your bike and run through mud in the woods without damaging your cleats. Road shoes also tend to have the distinction of looking as though they were designed and colored by Peter Max on LSD. That reason alone would be enough to make me use the off-road shoes, but the recessed cleats are really the deciding factor. I like to walk around looking a bit more like a human being.
Pedals are also broken into those same two classes. Road pedals are more aerodynamic and lighter than off-road pedals. Off-road pedals normally are two-sided, road pedals are usually single-sided. I started out with road pedals but, became frustrated with the difficulty in flipping them over at certain points. I figure that even if they saved me a few seconds by being lighter and smoother, they more than made up for it when I was at a stop-light flipping them over. I guess if you are racing you clip in once and forget about it.
Whatever pedal/shoe combination you buy, make sure they are not too tight locking in. It is going to take a lot of practice to be able to clip in and out of them at a stop, and you will probably get to do a few of those cute maneuvers where you come to a stop and just fall over in slow motion, like a giant redwood felled by the axe of an imp named Igor.
Anyway. Get some. Practice. Keep them clean from dirt. Practice. Get them adjusted. Practice.
Oh, but -p l e a s e- don't get some the day of your century ride. You need to... what's that word? Oh yeah - practice - before you take on a major ride. Don't show up at a multi-day event and decide it's time to switch to clipless (as they are called) pedals. Everyone asks "Why are they called clipless when you clip in and out of them?" The answer is simple, we do it to confuse you. However, we like to tell people that it is because the alternative is toe-clips. Since these don't have the toe-clips, they are clipless? Capice?