On the conventional side, Pennzoil Air Cooled (found at most AAP's), or Super Tech Univeral 2-Cycle Oil (the one in the Clear bottle with the measuring spout), available at WM.
I don't know what kind of saw you have, but a lot of folks report great results with Stihl HP Ultra synthetic 2-cycle oil, available at most Stihl dealers.
I've had good results with the Weedeater Synthetic oil, bought at WM. (Made by Husqvarna Outdoor Products)