If you are considering Affiliate Marketing you should seriously consider Product Review Websites
Visitors to review sites are looking for their opinions to be confirmed prior to buying what they already wanted, so confirming their opinions & adding your affiliate links just prior to them buying is a formula for success.
Affiliate Review websites also have some major advantages over any other type of website you may be considering.
Your website content is already 90% complete!
All the products details, benefits & specifications are listed on the vendors sales pages, although it is not recommended to copy the information verbatim it is simple process of taking the main features & benefits, & putting your own spin on them. Remember you are reassuring the reader about a decision they want to make so your reviews should emphasize the products benefits. You can list the specifications but they should not be the primary focus of any review.
Web design & structure is already predetermined as a review site, so building your site is easy using pre-configured templates or Word press plugins.
Your main keywords will undoubtedly be the products themselves, It is a simple process of including associated keywords within the reviews of your primary & secondary products. Visitor comments will keep your site fresh & frequently crawled by the search engines, make sure you set the comments to require your approval before they are posted.
In conclusion reciew are easy to build, write & S.E.O, they are also perfect candidates for P.P.C. (Pay Per Click) promotion. Your site will have a very good quality score for its main keywords, keeping your cost per click down & your conversion rates will be high because you are targeting active buyers.