There are two basic types of wedding bands: straight and contour. A straight wedding band is the more classic style. It's a continuous, uninterrupted circle that represents the eternity of a marriage pact. A contour wedding band is a more modern variation that is made to follow the contours of your engagement ring.
Below, you can see how an engagement ring with a woven, pavé shank would look with the two different types of wedding bands. Some engagement rings, such as this one, work with both kinds of wedding bands.
More unusual engagement rings, like the antique ring below, are so long down the finger that they require a contour wedding band.
Are you going to wear your engagement ring every day? If not, make sure that whatever wedding band you choose, you'll be happy wearing it by itself. Sometimes contour bands can look lonely if they aren't worn with their matching engagement ring.
It's a good idea to think about what kind of wedding band you'd like when you're designing your engagement ring. They're going to be a pair, after all!