com, net or hyphen?

For the purpose of a niche site, would it be better to hyphenate a domain name and use dot com or no hyphenation and use dot net?

For instance, if the site was about dog collars is "dog-collars.com" preferable to "dogcollars.net".... or would it make no difference?

here are my preferences in order

1. .com
2. .net
3. .org
4. .com with a -
5. .net with a -
6. .org with a -
7. .com with a suffix
8. .net with a suffix
9. .org with a suffix

dog-collars.com vs dogcollars.net

i choosen dog-collars.com

SERP rank well for non hyphens.. whatpeoplewant.info better than
what-people-want.info

I agree with what everyone above has said.
Copy what Voxclan said into a file - he's summed it up well.
I personally though would choose a dashed .com over a .net but you just have to figure out your own rules and go with it - otherwise you'll waste all of your time making decisions instead of getting something done.

If you ever wondered why .com is favored by google I'm guessing its because you actually have to pay good money to get a good domain name. You aren't going to pay good cash and put up a piece of junk website.

Thanks very much to all the above posters!