I was thinking about this thread when the ST is finished. I actually think 4,5,6,1,2,3,7,8,9.

Now many would argue if you are going to start with 4,5,6 then you should go right into 7,8,9 then 1,2,3. But my reasoning for this is after watching 4,5,6, episode 7 takes place 30 years after. So by going back and watching 1,2,3, and then when you watch Episode 7, it will feel like a much longer time gap since you have seen Episode 6, which will jive better with seeing the characters much older now.

I hope that makes sense?