I am asked often how much content that a page should have. Kinda goes along with KeyWord Density things as they are tied hand in hand. There is no actual number as to how long or how short in content you page needs to be. Some pages do well with just a few paragraphs and others need much more. I would not have less than 100 words personally.
I would keep to less than 2 links per page and keep it simple. If your site is about a subject like gum then you would not want to talk about automobiles. You have to keep it on topic. This site for example is about SEO / SEM, Social Media and Motorcycles. Yeah motorcycles might seem like off-topic but I ride everywhere.
So when you are writing your content, write for the user not for search engines. If the content does not help the user then the content is crap and is is just fluff. So in summation, write about the subject. You can then do other posts in a series or you can have other items in an E-Commerce that you can link to or talk about in a natural way. So how much content do you need? As much as it takes to make sense.