Use what you have. The story and ability to put a story up on screen is more important to start with than any "What camera should I have" decisions. You could listen to your friends and spend a bunch more $ on a different camera, or you can figure out how to use what you have and spend the $ on the production.
Both Sony & Canon cover the gamut of camera qualities, from (relative) junk to professional.
Without knowing exactly what you have now, one can't really make any comparative comments.
A straight "Canon vs. Sony" debate is meaningless, in the greater scheme of things anyway.
Oh, and as the others said... there are other more important parts of filmmaking than owning "the best" camera. While it's certainly nice to have a fancy one, it's more the icing on the cake than the real beef.
What do you have now, btw, and how much were you considering blowing?
You have to set yourself a budget first and decide what you can get for your money. I would'nt narrow my search to just Sony and Canon though. The one thing I would suggest is buying a 3ccd camera if all you have is a 1ccd now. Panasonic has a line of 3ccd cameras out right now for under $1,000. Some you can get used on Ebay for around $500. If you have more money to spend you can get a Canon GL1 (what I have) for a little over $1,000, usually around $1,200. Research all cameras though, JVC has a pretty cheap high def camera, the gr-hd1. Just read before you make any big decisions though.