It's important to know where you are going and how to get there. When I lead trips I'll generally carry a water proof topographic map (a map that shows elevation changes) and I will give people on the trip a paper map so they have some reference of where we are and where we are going. Generally the group will stay together so one person navigating is fine, but I'm of the opinion that everyone should be aware of where we are and where we are going. A map and compass are of no use if you do not know how to use them. You should take time to become familiar with them or ask the trip leader to explain it to you.
An important note about the use of GPS: GPS (Global Positioning System) is a handheld device that communicates with sattellites in orbit above the earth to tell you where you are. A lot of people buy these devices because they think the device will handle all the navigation for them. The truth is that most search and rescue situations are to rescue someone who went out into the woods with a GPS and they didn't know how to use it or it didn't work. A GPS unit is a piece of technology, it can and will fail (though you probably didn't invite Murphy along on your trip, it's likely he came anyway). A GPS will also not work well in heavy tree cover, so if you're in the woods you might have trouble. Take time to learn the proper navigation techniques so you know how to properly use your GPS unit and you know what to do WHEN it doesn't work.