We have a 24 foot 2000 Winnebago Minnie (shown in the picture at the top of the page) that we bought a year ago. It's a Class C motor home. The best way I can describe the various classes is that a Class A motor home is built from the ground up to be a motor home. These are the big bus like RV you see. A Class B motor home is a modified van with a raised roof, and a Class C is a motor home built on to the back of an available truck frame. Ours is built on a Ford E-350.
Of course, you don't get very good gas mileage with these things, mine gets about 8 MPG, but it's a trade off. A motor home is a lot more comfortable than riding in a car, you can bring plenty of food and drinks so you don't have to stop at restaurants, and you can generally get a campsite for less than $30 a night.
Modern RVs are fully equipped. There's a bathroom with a shower, a kitchen with a large refrigerator, microwave and convection ovens, and a stove. There's an electric water pump so you can have water while you're traveling, a water heater, and a generator to give you full 110 volt power.
Most campsites today offer the standard hookups (water, sewer, electric) as well as cable and wireless internet. Our RV also has a built in antenna with a power booster, so if we run the generator, we can have the TV on in the back while we're moving (of course you don't keep a signal for very long). We've hooked our son's PS2 to the TV so he can play games or we can watch DVDs on the road.
If you get an RV, the first thing you'll want to do is join an organization like the Good Sam Club. They provide you with discounts on things like insurance, repairs, and campsites, as well as provide forums to talk to other campers and to plan your trips.