George Carlin

From OAPedia.com

George Carlin is a legendary standup comedian. He has appeared on The Opie and Anthony Show, where O&A and Jim Norton acknowledged his influence. He is also infamously known for his "House of Blues" bit, which was repeatedly played during breaks in the early months of the XM show, before O&A had any sponsors to fill time.

On the November 17, 2008 show, Opie, Jimmy, and Patrice Oneal argued that Carlin is one of the top two greatest comedians ever (along with Richard Pryor).