What's better for my first short movie?

Is it better to buy a canon Hv20 or a Nikon D5100?

Added (1). Or a canon HG20

Defiantly a Nikon D1500! Nikon is a better Camera and 69% more used than a Canon!

Did you know that 68.537% of statistics are made up?

I'd go with the HV20 (or one of the more recent models) - video quality is excellent, you've more control, you can use an external mic, the video's easier to edit.

Neither.

Get a DSLR from either Canon or Nikon.