We didn't need Qui-Gonn.

I don't think Obi-Wan should be considered the best jedi ever. There must have been better Jedi Knights off screen that just didn't become famous for their actions, but were still excellent knights.

that's why I said (arguably)...he is certainly in the top three...anyway...it's just to make a point of the midichlorian thing...

DNA does not make you the best...it's heart and soul baby!! (although good genes can't hurt!)

What was the difference between Qui-Gon and the older Obi-Wan? I can't see any.

Qui-Gon was more rebellious it seems, although we can't exactly tell what Obi-Wan would be like with the Council.
And I'm not sure Obi-Wan would have been so willing to let Anakin take part in the podrace just to help the Queen get to Coruscant. Qui-Gon is more of a risk-taker than Obi-Wan is and Obi-Wan also seems more knowledgable.

I think they are very similar. They both break rules and don't exactly tell the truth. Maybe Obi-Wan get's that from Qui-Gon.

Yes perhaps that was GL's intention to make them act similar.