Are you buying your first camcorder? Find the best for budget, regardless of format.
Are you replacing an older camcorder? If you don't buy the same format, consider how you're going to transfer old tapes so the footage can be easily viewed, i.e. DVD.
Try it firsthand in the store — Pick up the camcorder, carry it as you would if you were recording, and check how accessible the controls are.
Who is your audience?
What standard of quality do you need? Do you want these videos to look as realistic to your great, great grandkids as they do today?
Will you be editing your video?
Do you need still photos?
Will you be making copies?
Answering these questions will help you decide which camcorder is best for you, without going overboard.