Some of the stuff I lug around to video shoots
Mini-DV tapes are fairly inexpensive ($3-$4 each) when bought in bulk. Try to keep several blank tapes with your camera at all times. I can't remember how many times I've missed a great shot because I didn't have a spare tape.
Here is an important tip from the professionals about buying Mini-DV tapes: Always buy the same brand of tape. Do NOT use TDK one day, Maxell the next day and then Sony the week after. Different manufacturers use different lubricants on the tape surface. If you mix and match tapes, you can gum up the camcorder recording heads, causing the camcorder to die.
You are going to need something to keep the camcorder steady, and trust me, your arms are not going to work too well. Professional tripods can get expensive because they have fluid heads and foam-coated legs. Fluid heads make panning the camera much smoother, as compared to non fluid-heads where the panning will be jerky. Don't be fooled by cheap tripods that advertise as having "fluid-effect" heads. It is either a fluid-head or it is not.
Foam-coated legs are a good feature of higher end tripods. They allow you to carry the tripod over your shoulder more comfortably.
Monopods are one legged tripods, which are useful in crowded situations. They are also good if you are a short person and trying to shoot over tall people in front of you. Attach the camcorder to the monopod, and then raise it above your head to get the shot.
If you are interviewing people, the only way to go is with a wireless microphone system. Dangling cords are not only unsightly, but dangerous. Wireless systems have two parts: the body pack with microphone and the receiver. The body pack is about the size of a deck of cards and can be placed in the subject's pocket. The microphone is clipped onto the shirt collar, with the cord running under the shirt. The body pack transmits the audio to the receiver, which is usually attached to the camcorder. Expect to pay several hundred dollars for a good wireless microphone system.