If I could just put in my two cents on the midichlorian subject, I would say the concept of strength in the force being determined biological is far from stupid, makes sense, and does have similar precedent in other non-SW sci-fi works.

However, it really makes no sense in the context of the OT. Along with what everyone's been saying (it's a fantasy), it's clear that the force is something that could be learned by anyone, even if it's something that must be taught (jedi training). Besides Han and Motti's remarks, we must also remember non-jedis telling other non-jedis "May the force be with you," something that wouldn't make sense in a world with midichlorians, in which the force can only be with jedis.

Also, it annoys me that the moniker "jedi knight" has practically zero meaning in the prequels. It should be: those that know the ways of the force are jedis. Those who use it to keep the peace are jedi knights. The super powerful force user teachers are the jedi masters. This is what's implied in the OT and should have been in the PT.