I've never heard of arco either, and i expected a youtube video of that shell commercial about shell gas versus discount gas when i saw this thread. I use Conoco when i am at home in Olathe, or Shell in Warrensburg when i'm at school, but it looks like i'm going to be switching the Warrensburg gas station of choice.

Oh, Wikipedia told me ARCO stands for Atlantic Richfield Company.

 

ARCO= Atlantic Richfield CO.

 

Yay for me!