I would create my own ads with affiliate products that your niche would be interested in. Adsense is good, but a hard way to make any money unless you have tons of traffic.
Depends on who your visitors are, what your blog niche is and content. Its all dependent on your blog itself. Some methods are good for some, other for others.
If you are blogging in a niche where people are likely to purchase products/services online then it is best to go with affiliate programs, else Adsense or other PPC programs would be perfect.
ad sense and affiliate links. I think that is the way to go. But try not to overwhelm the visitors with too many ads or links.