I can't really choose, but if you really had to push me.... The CSIs. Why? Because you don't know what the actors will be like and since I would just really like to meet all of The LVPD Crimelab. And, eish, in the pole, there is no definate. 50 and 51 for each.... Wow, freaky! Kate.
Actors.. gives me the chance to talk about a lot of other stuff too. I think I could talk for hours with Jorja Fox.
Meeting the actors would be much more fun because they played so many different roles and you could ask them about that. And since so many characters on the franchise have so many "issues" they're carrying around, I would rather go for the actors (where I can't grant that they haven't big "issues" as well ...)