In your post, you've actually asked many questions on many different topics.
First you spoke of content. You have several options for content. You can write it yourself. You can go to sites like ezinearticles.com and find content relevant to the theme of your website, or you can buy PLR articles, and either use them as is, or rewrite them. My personal vote is always going to be writing your own content with occasional links to other content that you truly feel will help your visitors.
Next you spoke of a newsletter. I use aweber.com They run about $19 per month I believe. They are WONDERFUL. Once I signed up for them, I was really surprised to learn that many of the newsletters I already receive also use Aweber. It's a very easy to use system. Having a newsletter signup form on your site is a must.
Next you spoke of building the site yourself of buying a premade site with content. Even if you buy a premade site with content, you'll still need to update the site and add fresh content on a regular basis. I use a program called XSitePro
http://www.xsitepro.com/cmd.php?af=376142 It's a site building program. You basically start from a template and add in anything and everything you want. I chose the program because of its ease. You get a 200 page manual/tutoria which takes a few hours to go through and then you are set to go.
Next you talked about SEO. My recommendation is a class offered by a woman named Cricket. Her class is beyond amazing. And it's totally free.
http://www.gnc-web-creations.com/seo-optimization.htm This is the link to sign up. It truly was the best class I ever took. With the help of her class, I have been number one on Yahoo and MSN for quite some time for "beginner scrapbooking". On Google, I fluctuate in the top 10 depending on the day.
I hope that helps answer some of your questions.