If I build it, will they come?

I have been taking the time to evaluate my financial goals on various levels. Part of my plan moving into the future will include building web based businesses. My plan is to build 1 or 2 solid business models that focus on providing services on one site, and products on the second. I also intend to invest a percentage of the profits I earn from these websites on micro niche sites. These will be sites that earn $100 or $200 a month, but won't require a large amount of resources to maintain.

I am in the process of doing the research for the niche sites, but I believe I know what my primary website businesses will be. Before I invest my money and launch my business, I want to develop a clearly defined plan for accomplishing the goal I have for each of these websites. This leads me to the point where I am developing a marketing strategy for the websites. I don't want to use PPC and I am willing to put off profits for a few months in order to build a solid foundation that drives traffic long term.

I obviously began doing my research into SEO and the proper techniques for getting ranked in the search engines. I found myself on Wikipedia at one point and I found this page http://en.wikipedia.org/wiki/Search_engine_optimization. It provides a great history of search engine ranking which could have passed as a dissertation for someone in college. It does cover various techniques that can be used in order to improve how a website ranks.

I also found a number of services and websites that offer services for ranking in the search engines. I looked at a significant number of different programs available and came across a variety of different information and services that are offered. I found some sites that offer libraries of information on the topic of ranking in the search engines, and I found others that provided fantastic podcasts on the topic, as well.

So here is where you guys come in. Have any of you ever used a company like this before? I believe that providing useful, valuable, and quality content is essential for my success. How much should I outsource for my content, and how much should I write myself? Are there things related to SEO that I should be doing myself and not outsourcing, as well?