"And Michael Shanks as Dr. Daniel Jackson"

[FallenAngelII]

Then why aren't the main and obviously more important characters given the same prestige?
I think Joe Flannigans agent would argue that he and his character are far more important then Beckitt and would be up in arms if it was a negotiable matter and Flannigan was put on the back burner.

I strongly believe it's solely for advertising the characers people might like, or heard of, or prefer, and hence stay tuned.

Being first in the opening credits is equally as good as being last and with a "And & As" or "With & As" because studies have shown that the actors people remember the most are those credited first and last.

I think another factor played into why Michael Shanks and Paul McGillon were the ones who received the "And & As":es:
* Michael Shanks left the show for a season and then returned
* Paul McGillon was a supporting character who wasn't shown that much

When they were added and re-added to the credits, they received "And & As":es to make it easier for people to remember them as some people might not have known/remembered who they are.

Of course, this is but one of many factors, as those I've already mentioned.

[senordingdong]

You've practically agree with me.

[TheUnknown]

Having several actors credited with "And & As" has happened before. I think it happened in season 2 of Charmed and one of the Buffy seasons. I could just be randomly making things up without knowing it too.

Yeah, I believe it was "And Anthony Stewart Head as Giles" for seasons 1-5, and then "And Alyson Hannigan as Willow" for season 6-7.