Just purchased NWN2 via the sale and am curious. What are the best settings for the different cameras in gm?

It's situational, and very much a matter of taste. Personally I like an RP feel so I use the down and dirty view most of the time but it can be awkward, even unwieldy, until you've mastered keyboard movement so even I switch to strategic mode in a fight. You'll need to decide for yourself what settings work best for you.