SEO Thread - Masters get in here!

I have a few questions for you SEO guru's out there

As I understand it there are some basic thing in SEO that needs to be in place but I have now read on many different boards and many different articles and a lot of them is contradicting each other.

So Please only answer if you feel confident that you know the answer:

Rules for backlinks(inbound links)?
Can you have too many?
Is it important that they are 100% relevant or could you link from tgp's to gambling sites?
What should the Anchor text be?
other things to notice?

Rules for Keyword density?
which % is the optimal keyword density?
how many keywords should a page contain?

Rules for Meta tags
what should a proper metatag look like?
when do a search engine consider
describtion, keyword, title spam?

Content is king
How much does content affect your rankings?

Domain name
How much of the ranking comes from keywords in domain?


I honestly have no idea if people will answer this but I think it could be a great noob thread if people would do it...

Hope someone feel the need to put in their