The best way to deal with water spots is to not get them. Try to wash the car in a shady spot if possible. Dry it off quickly after washing. I use my back pack leaf blower and then finish with an Absorber and micro fiber towels. If you let the car "air dry" or sun dry, your going to end up with spots regardless of what product you use.
If you get a good coat of wax or sealant on it, you shouldn't have much trouble with drying it. Most of the water will just beed and run off the car.
If you have some money that you don't need, the CR Spotless filter system pretty much eliminates the worry of water spots. It deionizes and filters the water so that even if you let it dry in the sun, you won't get water spots. I've heard very good reviews on it, but its a bit to spendy for me.
If your talking about getting rid of spots that you already have, than it really depends on how bad they are. If they're on the surface of the wax or sealant you shouldn't have much trouble getting rid of them, but if they're etched into the clear you will most likely need a machine and some good polish (or sometimes even compound) to get them out.
Pay attention to the water you are using. The minerals in the water create the water spots so well water will be worse with water spots than treated water. The filter for your hose should be worth the money if you are getting really bad spots.
ducky's water spot remover works pretty well as well, it's made for boats to remove water spots. i've used it and it does a good job, however, prevention is the best bet.