Flash 8 or Flash CS3

I’ve been working with MX for a while now and I feel its time to upgrade. I was wondering what you guys thought about Flash 8 and CS3 - are there any reasons to go with one over the other?

I assume it would be easier to learn AS 2.0 but at the same time I don’t know if I want to learn a new structure if its already dated given CS3 is on AS 3.0.

Basically, just looking for some kind of comparison or suggestion about which version to go with. Thanks.